1) Keep locations down to a minimum. The last thing you want top be doing is wasting petrol, time, and money zipping from one location to the next.
2) Employ friends as cast and crew members, sure, by all means, but just make sure they are motivated and talented. Above all, make sure they are willing to devote Saturdays to helping you out.
3) Keep the story simple. Do not overwhelm yourself with too big a canvas. Keep characters and situations down to a minumum.
4) Make sure your actors are at the very least semi-professional, and able to learn dialogue and recite it the least bit realistically.
5) Let people know ahead of time when you will be needing them. Plan, plan, plan!
6) Never leave anything until the last minute. The last day of filming should be fun and relaxed.