I have found some specialized tools that I need for model building that I did not have for miniatures. I started out by trying to do without some of these but finally I have broken down and purchased them and I don't know what I was ever thinking trying to do without them. All should be available at stores like Eric Fukes.
Sprue Cutters - Specially made cutting pliers that snip models off of the mold sprues. These make a big difference over just breaking the parts off the sprues. The specially made cutters leave no sprue and cut clean enough that you don't have to go back with a knife to remove the last little bit of sprue. In a pinch, you can use a pair of nail clippers and a knife to do a similar job.
Liquid model cement - Model Master makes liquid cement in a black bottle with a syringe like applicator. This is morth ten times the $3.00 price. The cement acts much faster than normal cement and the applicator is great.
Clothes Pins - The ones with the springs in them - make excellent clamps for fuselages and other parts - get about six to eight on your workbench. Also use some heavy objects for weights in glue-up. I use Dullcoat bottles.
Super Glue Accelrator - Spray accelerator for super glues is a must for tricky set ups. This stuff really works great! Well worth the expense. Many models have metal parts that must be attached with super glue. I also sometimes use super glue when minimal set up time is desired.
Decal Set - made by testors. This stuff is really magic. Follow the instructions on the bottle and your decals will come out great. I swear by this stuff.