In my 12-team roto keeper league, we draft in reverse order of the standings: 12th place team gets 1st pick, 11th gets 2nd, etc. It's very simple and works well for the teams trying to contend, but it does encourage teams with no chance to deliberately tank their teams. We've had one guy finish last in 3 of 4 seasons.
Personally, I think I'd prefer something like the top 3 teams get to pick in reverse order but everyone else is in a lottery for picks 1 through 9.
We've also tried all kinds of stuff to try to help the bottom-finishing teams improve. Last year, the top 3 teams got one less keeper than everyone else and we gave the bottom three teams the option of keeping less players in exchange for more 1st-round picks. But it didn't work. The bottom teams didn't take advantage of the extra picks. Unfortunately, the bad teams are bad because their owners are bad owners. Nothing you can do about that.
I am the Master. Don't question the Master. Just do what he says and be proud.