If there's somebody worth getting with that #1 pick, then do it. If you want a d-linemen but none are rated as Top 10 draft picks, then you really won't get what you need from the trade. Go through scouting and find one or two guys you really want to get, and start the draft. Wait a few picks until you think the guy you are targeting is going to get picked and then try to make a trade. If you wait till like the 10th pick, you won't have to give up nearly as much as you would for that #1 overall.
As for my trades, the further along I get in my franchise, the more trades I tend to do. I traded Keyshawn Johnson, my 3rd round pick and an O-lineman rated around 80 to the 49ers for Brendan Lloyd and their first round pick. Lloyd's contract was up after the season and he was a restricted FA, so I made an offer but somebody matched offering me the 19th pick in the 1st and 3rd rounds, so I took that deal. I had 3 1st round picks(18th was the highest since the 49ers went on a tear after getting Keyshawn!). With those picks i got:
-CB rated 76 at the start of the season, 99 speed
-LOLB rated 74
-QB rated 70, but has 85 speed and 92 Throw-Power
So it worked out pretty well, I'm probably gonna deal Henson in this offseason for a top 10 pick so I can give that 85 speed guy a shot at starting, he was a lot of fun to use in preseason games!