Tactics
Here the opinions are different, but I had the best results with short passing style, pressing from minute 1 to 90 and also hard tackling. For this you'll need players with high passing attributes and a good stamina. In my games I mostly play a self made 3412 or 4312. To download this two or one of many other tactics just follow this link!. After downloading just copy them into your CM3 tactics folder.

Training
After trying out some things now I always use this training schedule:
Goalkeeper: gk: intensive | tactics: medium | fitness: medium | skill: medium
Defender: tactics: intensive | fitness: intensive | skill: medium | shooting: medium
Midfielder: tactics: medium | fitness: medium | skill: intensive | shooting: intensive
Striker: tactics: medium | fitness: medium | skill: intensive | shooting: intensive

General training tips
To increase positioning, you've to give your players goalkeeping training.
Reserve players, especially the younger, can get a harder training, with three or four areas of the training intensive (I know I'm sadistic...).
First team players who always have a bad condition should get a "softer" training.

National manager in the first season
At game start, look out a team where is a player whose country you want to manage. Click on the players nationality to view the international squad of his country. Now click on "control" and you're the manager of e.g. england. -> You can only become international manager of a country that you're running (fore- or background).

Save money / signing on fee
When you buy a player, always put the signing on fee down to 0. This will save you millions! The signing on fee seems to have no influence when you want to buy a player, so you can also put it down to 0 when there are offers from other clubs.

Save money / release clauses
You can save some money in players wages when you offer the player a relegation and/or non promotion release clause (when he doesn't request this clauses).

Assigning good staff
When you're looking for your new coaches, scouts,...what I'm doing at the start of every new game, then NEVER look only for interested. The most coaches I have were not interested. Better do this: Filter out what you need (coaching outfield players, motivating...), and make your offers (I mostly make offers for at least 20 coaches). How many agree with you depends on their and on your clubs reputation, but even with conference teams you can get some really good coaches.

Get a player for free
You (e.g. Arsenal) make an offer of 0 for a player. Then add another manager of any team (e.g. Tottenham). Now offer with Tottenham any amount that you want for the same player. After this click on "change Transfer Bid". Now you see the details of Tottenham's transfer bid. Go to the top left of your screen and click on the little arrow, and your clubname (Arsenal) appears. Click on it. It appears a screen with the details of Arsenals bid, now just click on accept. Now withdraw the Tottenham bid (or resign from the job) and offer the player a contract. This cheat works with any player, of any value and from any club - when he's interested. This cheat is submitted by Paul Sharpe.

Signing Players on a Free Transfer
When you've problems to sign players on a free transfer, do this: First, offer him a trial. Maybe he's interested now, but if not, then offer him a contract with one, two or all three release clauses. (The minimum-fee release clause should ever be the last you offer) With a bit luck you can get him now.
When you're managing a very small club: Check out free transfers from eastern europe! Especially belarus, but also slovenia, croatia and yugoslavia. Some examples? Sergei Vekhtev, Sergei Gerasimets, Sergei Shirokyi, Robert Belec, Robert Vladislavic, Nenad Maslovar. But before signing 7 or 8 of them first look how many non-EU players are allowed to play in your league.

Release Players on a Free Transfer
When you release a player on a free transfer, you have to pay him compensation, depending on his wages and the length of his contract. You should ever try to sell him for some time before you give him a free transfer, even when you set his asking price down to 0 it's cheaper for you.

Sell players / make clubs interested
When one of your players is transfer listed some time, and no club is interested in him, take him off from the list and directly transfer list him again. Now sometimes you've the luck that someone is interested.
If you take him now of the list, the offers for him will be higher.

Sell players / get more money
When you see that a club is interested in one of your transfer listed players, take him off from the list. You mostly get more money for a non-transfer listed player.

Buying players
To get that annoying player that won't come to you but his wages are in your reach. Add another manager and then manage the team of the player that you want to buy. Put him as not needed by the club and relegate him to reserves. If he still doesn't want to join your club try to release him on a free, maybe you've to wait some time until the board doesn't think of him as an important player. Now you can get him. Of course that won't work to get Michael Owen to your Conference team, but you can get some good players this way, and it'll also save you wages. (submitted by Keef Hunt)

Make profit with transfers
When you make a bid for a player, offer his club 0 up front but millions after 10 league appearances (In most cases the players club will accept this offer). Play the player for 9 games and then put him on the transfer list - And make a large profit! (submitted by Shane Coyne)

Save money on wages
If the player is below the age of 24, there is an option of making him a hot prospect for the future. Click on this rather than important first team player or indispensible player and it will save you thousands on wages. (submitted by Wassim Captan)

Sale a useless player for more money
When some team have made an approach for one of your players you have to try to exchange him with a valuable player of the other team and click negotiate. Than they`ll make an offer which is twice or triple more. (submitted by Jordan /bulgaria)

Work Permits (in england and scotland)
In england and scotland every player who is not from one of the EU countries needs a work permit. I'm not sure how that works in real life, but in the most cases in CM3 he'll get a permit if he has 10 or more caps for his country. This permit gets renewed every year if the player has done at least 75% of all the league games he's been able to play (games when he's been not injured, not banned or not away to play for his national team). If he lost his permit the only way to get it back is to sell or release him and then buy him back...

Get a player for free II
If you want to sign a player for free, say Owen, add a manager as manager of Liverpool, go to Owen's stats and release him on a free transfer. Now before pressing continue resign as manager of Liverpool. The board will not block his free transfer and you can sign him with the club you are playing with properly (he must be interested, though...). If you do this in the first couple of weeks time goes by so quickly that he will be released and some other club will sign him, so wait a couple of weeks. (submitted by "Gazza")

Bankrupt a club
Sometimes it could make fun to totally bankrupt a club...;) To do this add another manager controlling this club. Offer some players a contract with the highest possible wages and the longest deal - After they accepted release them on a free using the cheat above (get a player for free II). (submitted by "Gazza")

How to make a screenshot
How to make a screenshot? Hit the "print" key which you should find right from "F12", then run paint, Paint Shop Pro or something like that and "paste" it there (mostly with Ctrl + V). If you want to send me that shot (e.g. for the strange CM happenings), please save it as a Bitmap (*.bmp) and use e.g. WinZip to compress the file.
Still one thing, if you're playing CM3 in windowed mode, hit "Alt" + "Print" to make the screenshot.

Win an already lost match
With Manchester United losing about 5 or 6 games mostly away to Arsenal or some big club I used the 3-5-2 attacking formation with normal tackling short passing a pressing, I always take off at half time players at 5 or lower and at the 65th minute I take off players with ratings of 6 or lower, mostly the strikers or midfielders, and if I am losing then at the 80th minute I move the AMC forward into the centre of the 2 strikers and the CM forward to the right and left of the original place of the AMC and leave the midfielders where they are. This tactics sometimes fails on a bad day or if the opposition is quite hard, e.g. Arsenal away only. But against all teams especially when you are away and they attack will be killed by this tactic, it is also a great comeback tactics... (submitted by Rob Blowes)

Sell your players for as much as possible
If you put your player on the transfer list and someone makes an offer, negotiate and ask for some more money (not too much more). If they make a new bid, reject it. Now remove the player from the transfer list and directly put him back on the list, probably he'll be wanted again. Do this until the club doesn't want him anymore, then you'll know the maximum price that they're willing to pay & you should be able to sell him for... (submitted by Augusto Lenzuen)

Get more money from your player-transfers
To make more money on the transfer market when you're selling a player, negotiate an offer of (e.g.) 4 million to 3.5 plus about 7 million after 10 games. The chances that the other team accepts this negotiation aren't bad - now the player just has to play the 10 matches, and you'll get some extra money... [by Niall Condren]

U know another good trick or cheat? Mail me!