Professionally, I'm a salesman, so I'm really interested in the whole persuasion and influence thing. As far as I've found, the best sources for ideas on suggestion and "subliminal" influence that could be applied to magic are Richard Bandler & John Grinder's "Trance-formations" & their "Patterns of the Hypnotic Techniques of Milton H Erickson"). Or for something more specifically magic-based, Kenton Knepper's Wonder Words CDs and accompanying workbook are good. Although, as OwnerM says, Derren Brown's "Tricks of the Mind" is a good basic introduction, as is "Building Blocks" by Luke Jermay and "Sleight of Mind" by Ian Harling & Martin Nyrup.
Personally I don't do any structured suggestion-based routine, but I occasionally do stuff like making people forget their name, imagining a card to be a different one and that kind of thing, which, when you learn the fundamentals of suggestion and have a bit of practice, are fairly simple to pull off.