I offer three methods to my players.
1) Straight Roll, reroll any 1 once. (if you roll 2 1's, you get a 1)
2) Fixed Score, 1d4=2, 1d6=3, 1d8=4, 1d10=5, 1d12=6
3) Median Roll, Roll three of your die type. Pick the middle result. If two numbers (or I suppose all three) tie, then that tie...