For others you may want to post the league's settings, H2H, points, or roto? 5x5? standard? starting requirements? I'm assuming standard 5x5 roto. Here we go...
-The catcher position is scare. If you miss the top 5 though, don't reach too much, don't fret. Bengie Molina's a good value deep in the draft. Justin Towles and Geovany Soto are a couple of low risk high reward type players too
-No matter what anyone tells you, MI is deep this year. If you miss on the elite guys don't go reaching for a 2B as a value like Kendrick, Polanco, or Kelly Johnson will be waiting for you much later. As for SS, there is a huge drop off between 3 and 4. If you miss the top 3 you may be best to give up on SS until the late rounds and pursue a Yunel Escobar, Jhonny Peralta, or Khalil Greene type unless a Tejada or Furcal falls far enough in the draft
-A good pitching staff can be assembled even by not taking your first one until round 8+, do not under estimate the value of middle reliever's. You can draft a SP with a slightly higher expected ERA and compete with the elite staff's by adding quality middle reliever's later. High upside guys like Lincecum, Liriano, and Sheets early and Harden, Randy Johnson, Sheets, Buchholz, and Bonderman later are worth the risk. Use steady, under valued starters like Derek Lowe, Greg Maddux, Pedro Martinez, Good Weaver, and Kuroda (I think he's safe even though he's never pitched outside of Japan) to balance out the risk of your other pitchers.
-Do not be the guy taking a closer in the first 120 picks, 35 saves can be found much deeper in the draft in guys like Joe Bo, BJ Ryan, Percival, and Soria. The solid ratios provided by the elite closers can be found in the elite middle reliever's that will be available deep in the draft, your Heath Bell's, Rafael Betancourt's, Jonathon Broxton's, etc. will help balance out any disadvantage you may have from not having an elite closer with elite ratios
-In the early rounds try to draft balance, meaning draft 4 and 5 cat players instead of 2 and 3 cat performers. Focusing too much on R/SB or HR/RBI early will limit your options later in the draft. Guys like Markakis, Chris Young, Pence, Corey Hart, Sheffield, Abreu, and Matt Kemp (notice that all those I mentioned are OF's) are more valuable than they're normally drafted.
-You can't win your league in the first two rounds, but you can lose it. Don't be that guy going after Albert Pujols.
Hope that helps, good luck, and welcome to the wonderful world of fantasy baseball! I promise you'll get hooked.