Iggy pretty much sums it up. Timer can work well if the time exposure is under 30 secs though also. If it's daylight then putting on your CP or ND filters will help darken the sky a bit.
Lightning is usually a fair way away when you shoot it (hopefully) so manually focus on something obvious, or if you can't see anything in the dark and gloom then set the focus to just back from infinite usually works well.