Tactics
Here the opinions are different, but like in CM3 I had the best results with short passing style, pressing from minute 1 to 90 and also sometimes hard tackling (and there I'm not the only one, also submitted by Chris Philcox). For this style of play you'll need players with high passing attributes and a good stamina. A very good working tactic is Marc Vaughan's 4132 one, which you'll find (beside some others) in the download area. After downloading just copy them into your CM99/00 tactics folder.

Get "only recently purchased" players more easily
Some players can't be bought as they are only recently purchased (or you've to pay lots a time the money he's worth). When a player like that is available on loan, then loan him out and try to buy him again - suddenly they forgot that he's only recently purchased. [submitted by Eric van Buuren]

National manager in the first season
The same way it worked with CM3: 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. -> Only works with the 16 countries which leagues are included in CM99/00 - no matter if you're running them. (Also works with "Add manager" in a running game)

National manager in the first season II
Start a new game and select your nationality as usual. When you're asked to choose your team click on the nations- abbreviation which is between the teamname and the abbreviation of the league. (Sunderland   ENG   PRM -> click on ENG) Now click on "control" and you're the manager of e.g. england. -> Only works with the country whose league you choosed to play (Also works with "Add manager" in a running game) [submitted by James Koch]

Get your players for (nearly) nothing
1. Loan a player
2. Make an approach to buy the player for 1k (or more if u want...)
3. Select the "Transfer" button on the players profile screen
4. Here you see the offer you've made - click on it
5. Once you have accepted the offer, go back to your news screen
6. Now you're able to offer the player a contract!
And as it seems that also works if you don't have any money! [submitted by Jan Zakutelsky & Stuart Capel]

Score more goals
Get a strong player with a good determination and heading and let him man mark the oppositions goalkeeper. It seems that it doesn't work with every player as this tip was submitted by a lot of people now and I could not really note a difference. [submitted by Luke Kavanagh and Ben Richardson]

Free Transfers
If you're managing a smaller club, always look out for players who are available on a free transfer. Send your scouts out to every region and shortlist every free transfered player you're interested in, also if he isn't interested to sign for your club. Every player will be interested to join you when he is jobless some time, you only have to have the luck that he doesn't sign for another club before...

Trick to sign free transfers
If there is a great player on a free transfer, but he doesn't want to join your club - offer him a trial and then try to sign him again. In some cases he'll agree with you now...and also for much smaller wages! [submitted by Gautier Ryckeboer]

Training Tip
"Select all your coaches to train everyone and all of my players improved in their stats. Select them all to train on general - it worked for me as I got Forest promoted in the first season" [submitted by Steven Swinscoe]

Get rid of unwanted players...
Especially interesting for the small club managers of you: If you want to sell one of your players and you get an offer - set his status as "not needed by the club" to be sure he'll leave![submitted by Gautier Ryckeboer]

Signing players
If a player doesn't come to you because you can't give him as many money he wants, offer him also a release clause. Especially the "minimum fee release clause" will help you to sign some players - but remember that you can't refuse any offer that meets that fee!

Get big players to small clubs
You're a small club? Always check who of the players in the major leagues is unhappy. Try the tip above (Signing players) and you'll get some of them even to your 3rd division club [submitted by Richie]

Get a player for free / Get rid of unwanted players
First of all, add yourself as manager of the player's club. Then set the player's status to "not needed" and "transfer listed", otherwise the transfer will be cancelled by the board as being not realistic. Now make an offer for that player and retire from the player's former club after signing him. Works with David Beckham as well as with the crappest player in the game. Another idea would be to add the second manager to a rich club, and then buy your unwanted players from club1 with that club. [submitted by superman and Ray Cunningham]

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 CM99/00 in windowed mode, hit "Alt" + "Print" to make the screenshot.

There's a tip or cheat missing here? Then don't hesitate - just mail it!