I'm going to be building my first motorized bike soon, and have heard this stuff works wonders. I'm just completely unaware of which bolts to use it on. Also, any other suggestions or recommendations would be greatly appreciated.
I'm with Crassius, after any install/maintenance, I'll routinely check on the tightness of recently reinstalled nuts...two, maybe three times, each inspection after a couple of rides. The nuts'll eventually get to a quiescent point where they're settled in and you won't have to worry about them again until the next time you loosen them. This goes for the head-nuts as well; all that vibration and heating/cooling cycling has a tendency to loosen things up at first.
PS: LocTite's GREAT when applied properly, but can be a real PITA when you need to remove nuts. You're gonna regret putting it on the rag-joint fastener threads once you need to remove a sprocket to replace broken spokes!
Blue can be used safely on any fastener you feel might be subject to loosening due to vibration. What you NEVER want to do is use the red, or permanent type on anything that you might want to take apart in the future. Permanent means permanent. You'll need to apply heat to break it loose and sometimes more heat than the surrounding area will tolerate.
I'm not a fan of thread locking compounds and don't use it on my bikes. But if you feel it necessary , go for it but never ever use the red stuff.