Being new to modelling, I think the main thing to improving your craft is to experiment. Poke around through the forums here and you'll find that everyone has different techniques, different glue recommendations, and you can find all sorts of useful tidbits. Remember, there is no right way to build a model other than to do what works best for you.
Most of us find that an airbrush is really nice to have. My recommendation in that department would be a Badger 200. Fairly simple for a novice to use, but extremely capable as your airbrushing skill improves. Poke through the airbrush forum for additional info such as paint thinning, compressors, etc. However, if you don't want to plunk down the cash for an airbrush, compressor, and paint booth, there are a lot of builders who do outstanding work with a brush. With good brushes and practice, you can achieve some pretty decent results.
I'll second Rebelreenactor's glue recommendations. I also use Testor's brush on liquid glue, that come in a clear paint bottle. If you're careless with it, you can make a mess, but with care it can glue things together really quickly so that your building is not hung up by parts drying. I also use CA super glue for that purpose as well.
For filling seems, I use Squadron's Green putty, Tamiya's basic gray putty, or CA super glue. As with everything, you'll find that as you use the different materials, you find which you can best use for whatever situation is at hand.
One last recommendation is to get one of those magnifier work lights, in which the light is a circular fluorescent light surrounding a large magnifying lens. Being able to see things up close and well illuminated can be a big help.
Have fun and welcome to the forums.