I've posted a couple of questions in regards to this in the play and help thread with no responses so far
1. Trigger stickers are not always to be found on the same level as the trigger and sometimes they are on the same level but later on so you have to back track or replay the level once you've got the sticker
2. Some trophies are very easy to get by going on the community levels, the levels will be called stuff like Trophy Heaven or 5 trophies etc.
3. If you are going to try and ace the levels personally I'd try the 'bunker' first, It's definatly the hardest and everyone else seems to have left it till last, but the way I see it is if you can't do that one you won't get the trophy.
You would have to get through all the levels once to allow you to play the levels in any order though
Hope this helps
p.s. If anyone else reads this, is there any chance you could read my questions in the play and help thread

I don't want to read a walkthrough just yet and like the op I don't want to spend hours doing the wrong thing.