Just a few more pointers:
Nippers or Side cutters!
Very useful tool! For me it meant a huges savings on bandages and band-aids. Instead of the repeatedly slicing into my thumb and fingertips with the scalpel I now snip the parts off the sprues with the side cutters. Select a type where the cutting edges look like this _/_ instead of this ><
The flat side will direct the force of the cut to one side so that the plastic in the part isn't stretched. Practice cutting sprues before cutting into sensitive/fragile parts.
Needle files. Stop cutting and scraping with a knife, X-acto or scalpel. Use fine files to get rid of moulding flash, remnants of injection gates or sprue attachment points.
Knife, X-acto, scalpel or whatever sharp edged tool you own: Save it for the very few cases when nothing else will work. It save a lot of work/cost for keeping the tool sharp.
Glue: Consider using a solvent to "glue" styrene,
this stuff is perfect: https://en.wikipedia.org/wiki/Ethyl_acetate
Hold parts together, apply small amount to joint with a small brush. let capillary action do the job, release parts after half a minute or a minute. If the parts don't fit tightly enough for capillary action to work you need to check the fit and/or apply force to hold the parts together. sometimes the little buggers are warped.
Heavy duty removal of parts or excess material:
Fret saw! It will get into the most inaccessible places to make that small precise cut and can be used to take out large chunks of plastic: https://en.wikipedia.org/wiki/Fretsaw
Don't go hacking with that razor sharp hobby knife (You haven't dulled it yet have you? See above.) to remove plastic. Drill a small hole and fret away.
Once you start airbrushing you will realise how much better coverage yoou get for less paint used. The airbrush actually saves on paint.
Whatever you do, use the Correct thinner for the type of paint you use. Even if it says Acrylic it doesn't mean that you can use water. Two brands of acrylic may not work with the same type of thinner. Ask here first.