I do all my trades based on watching football games and seeing
1) how players get the ball
2) how players get their yards
3) how strong / fast / agile they look
After week 2 of 2007, I was able to acquire Ronnie Brown and Adrian Peterson with a combination of Caddilac Williams, Joey Galloway, and Cedric Benson because the other owners were too involved in stats and based on rankings, Peterson was still not high enough to tilt the draft analyzer at that time. Brown was like droppable. I actually got Brown in every single league, and if it wasn't for the freak injury, I would have won most of them.
if you don't have time to watch the games, try NFL.com, they got a ton of videos. It's pretty obvious who's in a slump and who's overperforming when you see them play, so you can win alot of those buy low deals with a little bit of film.
I did this and offered Addai for Steve Smith, and Slaton for Randy Moss. Yet to see how that will work out, but I'm pretty sure Addai is not a top 25 player this year and is just in a good offense.