Be prepared. It'll ruin you for trout fishing for....well for me it was 5 years. I started in '99 banked one my first time out, 4 the second, and 6 the third time out. That was it for trout fish'n.
Funny thing was, I was warned about that - so I'm just passing on the warning.
As far as gear goes, that depends on the style/tactic you want to use. First decide on that, then you'll know what to get. As far as tips go, most guys on this board could give better advice than me. I've always fished off of the "feel" of the take, and swing from time to time (though not with a spey setup). There's indicators and stuff like that that can help, but like I said before, find out what appeals to you, or what's working where you fish then dive in.
The only advice I can give is to become a steelhead. By that I mean, read, study, watch video, dream, study water flows, ask more ?'s, repeat. And on those days when you get blanked...tell yourself that it was more about "just getting out". I hear that it makes you feel better, although it's never worked for me.
Hopefully that helps. If not, maybe others will chime in and help.