This one is easy guys, but so often overlooked by newbies. Gapping your plugs is a no-brainer and essential to having your engine running properly.

You need two things:
1: Spark plugs
2: Gapper tool (I got mine at Auto Zone)

All you need to do is set the plug on the gapper and slide it to the desired gap. If the gap is too small, use the hole to pull up on the prong without pushing down on the electrode. It's that simple. Here are some pics. Note: As defiant points out, there is a chance that a ramp gapper will lead to crappy measurements. A wire gauge is better, but I didn't have one on hand. Happy gapping!

I was PMed about listing gaps so here you go:
4G63T: .7 - .8 mm
4G64: 1 - 1.1 mm
420A: 1.22 - 1.35

[Defiant: Throw that ramp-gapper away, and get a wire gauge:]

Defiant,
Thank you for the edit and the photo. I have also changed the original post to reflect another issue brought to my attention.