Do the main missions first and you will get the Liberty City Minute trophy easily. Don't kill ANY pidgeons in the process. Use http://www.gamesradar.com/f/gta-iv-complete-pigeon
The other trophies are easy, the tough one is getting a turkey in bowling. Search how to get the trophy on youtube. And at gta4.net they have a checklist for 100% so create an account and use that, it works great!
GTAmissions on YouTube has great videos of every stunt jump.
Get your big GTAIV map out of the game case and then use a pen or pencil to mark where the jumps are and what direction to hit them from while your watching the videos.
Here are the first 10. http://www.youtube.com/watch?v=VWs-HiFb0Bg&feature
Look on the side panel for other 11-50 GTAmissions stunt jumps guide videos.
I think he has pigeon videos too.