Most things for building scooters are really straight foward once you get the general idea of how they work. If this is your first real scooter being built up, I suggest you learn about compression systems (
http://www.scooterresource.com/forum/showthread.php?t=41300)
Aside from that, a few tricks to make it easier are:
Making a bearing press to put in bearings, as hammering them in destroys them (
http://www.youtube.com/watch?v=ghv3Jfrd-N4)
Keep in mind you always need spacers in the wheel.
Also, always remember to grease all your bolts before putting them in, as they might seize under some circumstances. This is especially important if you run a Proto SCS.
As far as the headset, if it's not integrated, I highly recommend you take it to a bike shop to get it installed.
For putting grips onto bars, I find the easiest method is spraying Axe in them, as it dries up really fast and leaves no throttle.
For starnut installation, or other questions, try finding the answer in here:
http://www.inward-scooters.com/Frequent_Questions.php
Good luck on building up your own scooter, trust me, it's a lot more rewarding to do it yourself!
