Here are 13 of the most effective asking methods, 
with number 1 the most effective:

1. Face to face, two person team
2. Face to face, one person
3. Face to face, three person team
4. Personal letter with follow-up phone call
5. Personal phone call with follow-up letter
6. Personalized letter
7. Telemarketing (phone-a-thon) with follow-up letter
8. Telemarketing without follow-up letter
9. Direct mail
10. Special events
11. Canvassing (door-to-door)
12. Print ads
13. Collections (canisters)

From a TeamTrack workshop by Del Staecker