Dennis,
You'll find that everyone has their own habits and rituals that they fall into.
1. I usually send no more than two items- usually a card and a CIC, or just two cards.
2. I have a fairly lengthy letter that I type (I used to handwrite, after switching to typing I've found no difference in success rates). I also include questions for the player to answer at the bottom of the letter if they have the time. I've gotten 25 question sheets back so far.
3. I always handwrite the SASE and outer envelope. I think most people use a small envelope for the SASE and one of those #10 business size envelopes for the outer shell. I use the peel n' stick SASEs to make it easy for the players.
4. I don't use a sleeve or top loader for the cards so as to make it as easy for the player as possible. I never plan to trade or sell my TTMs, so I don't mind if they get an occasional ding or dent.
5. If you start to get really excited by TTMs, consider a subscription to sportscollectors.net. The best $15 you'll ever spend TTMing. The site has a ton of success and addresses and will save you a lot of time identifying people who never sign.
Again, these are just my own personal habits, and you'll develop your own. Good luck! TTMing is addictive!
Regards,
Mike