Here's a suggested setup for a 5x5, H2H league:
â€¢ C, 1B, 2B, 3B, SS, OF, OF, OF, Util
â€¢ SP, SP, RP, RP, P, P, P
â€¢ Five bench (BN) spots
â€¢ Two DL spots (* very important)
With this setup, you would be drafting 21 players (9 offense, 7 pitchers, and 5 of whatever you like).
Make sure you allow at least one, but preferrably two, spots on the DL. Someone on your team will inevitably get hurt, and it's nice to be able to put that player somewhere for safe keeping.
Set the minimum number of innings pitched in a week to 7.
Put a limit on the number of moves. Since this is your first league, I would suggest putting the number at something high, maybe in the 60-70 range. Set the limit for trades to 10, and let the league vote on trades with a 2-day reject time.
I would recommend starting a new league with 10 teams, not 12. Twelve-team leagues get kinda deep and ridiculous, although a limit on transactions would make that a little more manageable.
And one final suggestion: If you do create a 10-team league, set the trade deadline to the last day (it will be a Sunday) of the second series against the last team you play twice. Last year this date was August 6.