Don't be afraid to bench starters if they are doing poorly or have a bad matchup, assuming you have someone on the bench who is hitting well and has a good matchup.

Make sure you have as many closers as you can get. If there aren't any available in the free agent pool, consider setup men who are getting a lot of K's with good ERA/WHIP that might become closers if the incumbent is hurt or fails.

Make sure you have 5 or 6 starters and you pitch them enough to keep on pace with innings. If you have 5 starters and you always have them active for their starts, you should keep up, but I like to have 6 which allows me to sit one every so often if they have a bad match up.

Btw, when I say it's ok to bench a hitter or pitcher, there are a few guys (studs) that I never sit no matter how bad they are going.

Keep up with injuries. Sit guys that are hurt. Use your DL slots to maximum advantage. Lineups are announced about an hour before game time and if you remember to check in (yahoo puts an "x" by guys that are not in the starting lineup), you can swap out for a bench guy who is playing if you do it before the game starts.

Make sure you keep on pace for games played. If your second base position is on pace for a -10 games, that's 10 games worth of runs, rbi, etc. that you are potentially missing out on.

Offer trades to make your team better. Ask people what they need and trade from your strength to make your weaknesses better. For example, I've got lots of good OF but I'm weak at 1B and 3B. Wanna trade? Use the yahoo software to send an email to the whole league, and post it here as well.

Check the free agents available. Don't be afraid to cut your worst batter or pitcher and take a chance on someone who is available.

Look at the standings and see where you can make up a lot of ground quickly. If you are 8th in runs but only 3 runs out of 3rd, you can get 5 points quickly by picking up a free agent who scores a ton of runs.

Finally, ask more questions...