As I have written elsewhere, recruiting an affiliate into your program is only half the job done. You need to motivate them to get active. And one of the main places to call them to activation is your affiliate program’s approval email (aka “welcome email” or acceptance email). In addition to the call to activation (the motivational piece), you want your approval email to contain useful/practical information about your affiliate program.
Here’s the pattern I recommend following:
1) Remind them of your program details (often times affiliates apply to a number of programs at once; so it’s worth reminding them), and of your company (short but sweet, and motivating enough for them to start pushing you right away).
2) Include an activation promo (a commission increase opportunity, cookie life increase, etc). Activation, as used here, should be understood as putting up your links on their site(s).
3) Include a performance-based incentive (e.g.: cash for a certain number of sales referred by the end of the first 45 days since sign-up, or alike)
4) Enclose pre-coded affiliate links in your e-mail. Make it easy for them to get active with your program — as easy as a simple cut-n-paste job. If you have coupons that they can start using right away, include details of 2-3 of those as well. If you provide affiliates with access to your product feed, supply them with the details on how they may access one.
5) In conclusion, assure them that you are there for them, and provide them with your detailed contact information. If you have a capability of putting together custom coupons and/or creatives, do mention this too.