Hey buddy,
There are some GREAT tips in here! You brought up a good question!
Here's what I use:
a. Super Glue(a.k.a. Zap-a-gap, super glue gel, krazy glue, whatever...)
b .Testors Cement(not used very often, but if you want a good STRONG bond, its worth the wait for it to set)
c. Elmer's glue(for canopies/windsheild glass)
The super glue is great because it bonds in seconds(but can be tricky, so make sure the parts are aligned!)
Testor's Cement just needs either a jig, clothespin, or plain old rubber bands to hod it in place while it dries(at least 5-6 hours--don't use too much or your'll warp the plastic!)
And lastly the Elmer's--IT DRIES CLEAR!! Doesn't leave a haze(super glue can do that), and if you mess up it just pops right off! The only thing you have to do is be patient enough to let it dry.
Hope this helps!
Carlos