I share your pain. I also suck at tactics, but recently I convinced myself that it's not the rating that matters, but the fact that you have to practice religiously every day (or as often as possible). I have most certainly seen the difference in my games, even though my tactics trainer rating is not impressive at all.
My advice would be to try difference sites and do some tactics from books as well to keep things interesting.
Whats the trick guys? I do tactics trainer religiously everyday. Some days I'll be on a roll getting like 9 out of 10 puzzles. Other days I'll fail 10 in a row. Maybe its the time pressure. I just can't seem to improve my tactical vision. Ive had a rating as high as 1750 on tactics trainer only to fall back down to 1450. Anybody have any useful exercises to improve on tactics, or is the key to simply just keep doing em?