In my experience, patience, a good light, a half decent iron and possibly some magnification is all you need. Straighten the pins on the new chips (dead important), line them up on the existing ones (make sure your pin 1 spots match up). Try genexias tips for soldering the pins down, with the right amount of solder on the tip it works a treat. Keep pin 14 out of the way and wire the pin on both chips to 123.

I would look at the pictures on this thread so give you an idea of which CPU pin to use, that's the bit I like the least. I sure that if mine fails it'll be that connection.