The standard way to check this stuff is to hook an ammeter inline with one of the battery cables and see how much current is being discharged from the battery. If you have a drain in excess of 30-35 milliamps then you will want to pull the fuses one at a time to see if it goes away. If you pull a fuse that causes it to go away then you will need to isolate whatever is on that circuit that is causing your drain. If you have pulled and replaced each and every fuse one at a time and still have not isolated it then you need to look into your non fused stuff like starters and alternators. Make sure that there are no loads on the system while you do these checks, like an open door or hood light or anything of that nature.

Mark