The following is a list of tools and their descriptions which may help you modeling. I recommend that you get a shoe box, small toolbox or Tupperware container to store them in. Definitely, get a rag or several rolls of paper towels and keep them handy. Use them to wipe spills up and to clean tools and paint brushes or dirty track and wheels. Guaranteed- you'll use that rag more than anything else.
-Needle nose pliers- get the kind with wire cutters in the end. 6" to 8" in length (about $12 to $15.)
-Hobby knife- X-Acto makes good ones. I like the medium duty aluminium models. Buy extra blades- and be sure they'll fit the knife. When using it, cut away from yourself and shave off small amounts at a time. A spare piece of wood works as a good substrate to cut upon. Keep old blades in a film canister or Altoids tin. When it fills up, toss the whole canister and start a new one! About $5 to $7.
-Rail nipper- (flush cutters- Xuron make as good pair for $10 to $12)
-Screwdrivers- Smaller sizes are needed; see if you can get a set. #1 and #0 Phillips and 1/16" and 1/8" Regular is a good way to start. Sets start at $10. I stay away from the magnetized versions of screwdrivers since parts in model railroading tend to be tiny.
-Tweezers- A good set is vital if you intend to do any detailing work. They are also used in building structure kits, scenic work, and decaling.
-Clamps/clothes pins/rubberbands- Use these to hold model assemblies to dry or as you work on them. Some people also like to have some small bar magnets and an old cookie tray for building walls; use the magnets to hold the walls upright.
-NMRA Gauge- for your scale- about $10 each. Lets you check tracks, switches, and wheels against the National Model Railroad Association's standards. Better for the advancing modeler.
-Mill file/ needle files- Files are necessary to remove flash (material left from plastic or metal casting). They're also useful when laying flexible track.
-Paintbrushes- (sizes 1,2,3)
-Soldering iron/gun and 60/40 rosin core solder; helpful when wiring.
Remember to take good care of your tools, follow directions and be safe.