While I love live drafts I also like the challenge of an autodraft. Its all about the rankings, and ranking by levels at each position and at spreading things out.
Determine how many players you need to rank, and add that many, or at least come close, e.g. 12 teams * 23 roster slots = 276 players.
I recommend at least 2 - 4 rounds worth of players ranked by best players overall. Make sure you rank players where you want them and only players you want that high. This is where a lot of people make mistakes with autodrafts. They rank based on a cheatsheet list, and they wind up drafting someone they dont want at all way too early. When I'm in an autodraft, I'm fine with whoever I get, because I had them around where I wanted them, relative to other players at their position and relative to overall ranking levels.
The autodraft will try to fill in your starting positions, based on the top remaining players in your rankings. So if you have an available 1B ranked at the top it will draft him. When its you next pick if you still have an available 1B at the top of your list, it will place him in your UT slot. This means you should try to break up the position lists a bit. This also means that even if you have catchers ranked 260-276, not a bad idea after the top 3, the autodraft will go down there and get the top available one bypassing other players ranked higher, if that slot is the last slot that needs to be filled in.
Then start a few positional ranks, e.g. 3-5 OF, then 3-5 1B, then 3B, then SP, RP, etc., based on how you want to fill in, and how you judge the talent levels at each position. Think of this as succesive layers of position rankings, e.g. your A players, then your B, etc. Reserves are filled in by position, after the starters are taken, the same way as the starters are. Keep these lists small so you dont wind up with 3 2b. 3 of the top 1b isnt so bad because they're probably bashers and can be used in trades.
Late in drafts the choices get slim. Make sure you get your sleepers into the action. If you handle the ranks well you'll get decent players at each position.
Logging in after an autodraft is like opening a Christmas present of your own fantasy team. Not quite as much fun as live drafts, but interesting in its own way, and not as hectic.