I suggest you get a quick release coupling for your airhose (unless the AB has got it already). This is a two part item that goes on to the end of the airhose as it connects to the AB:
https://www.everythingairbrush.com/airbrushing-accessories/hoses-adaptors.html
Everythingairbrush are very helpful. When connected, you pull it apart to disconnect the AB but keep the pressure in the compressor. This is useful for detaching the AB for part-stripping and cleaning, reassembling, recoupling and then shooting a final couple of mL of cleaner, or for continuing airbrushing with a different paint. A great timesaver.Also, get a set of those tiny bottle brushes for cleaning the tunnel of the AB. Everything
Airbrush sell those too.
Remember to drain your compressor tank (assuming it has a drain) after each use, letting the remaining air go through the drain, to prevent the inside of the reservoir from rusting.
On the question of how to remove and replace the needle. Harder and Steenbeck (who made my AB) advised removing and inserting from the rear. This is to prevent the notches on the shaft of the needle at the non-pointy end from wearing the seals as the needle is inserted. However, as I am a slow worker and don't use my AB intensively, I remove from the front and insert from the back, to minimise paint being drawn in to the body of the AB.
I agree with all that has been written above, adding (as Gern mentioned) that when you are about to AB a part, think how you will be putting it down to dry. Holding a wet part is not the time to be thinking about this. If it has an unpainted or dried side, even putting it down in a certain position can be awkward. With a small part, often painted all around, it needs something to hold it while painting and when putting down. A needle, pin or similar between the part and a big handle of sorts, which can be put down right way up and without falling over, is needed. With my 1/16 Royal-Royce main body piece, which had many curves involving turning the part around about all three axes, I screwed a dowel to its underside, the other end of the dowel being on a piece of flat wood as a stand.
When cleaning the AB, be VERY careful not to loose parts (as also of course when assembling a model). Work over a (reasonably heavy) box with sides of about 2 inches wide and tuck your stomach forward as close to the bench/table as possible, which should be pulled up close. Put each part down inside the box. Take care not to bend the point of the needle. Beware tweezers. As with assembling a model, held too hard the spare part can hit the carpet monster several feet away. When moving your hand over the box, avoid your cuff catching and spilling bits.
Have lots of paper towel stuff in small pieces for wiping. I use good quality toilet paper which doesn't seem to shred fibres when wiping, but use cotton buds (unless you are wary of them shedding hairs which never seem to bother me) or a non-shedding cloth on a stick to clean the insides of the AB.
Avoid spraying in a cold place. If inevitable, warm the paint, AB and the part. If you spray during hours of darkness, use a good general light source (eg., fluorescent).
Not every part or type of paint coat needs an AB. A brush can often be used, or a spray can including for gloss (therefore avoiding the need to clean the AB).
Here are the main variables involved: make of paint; thinning (+ Flow Improver); air pressure (most people use about 20 PSI); distance between nozzle and part; how think a layer to add (start with light coats when using matt paint); AB cleanliness. 6 variables. If only one variable is wrong (eg., not enough pressure or too thick paint etc.), there are 6 opportunities for a session to go wrong. If two variables are wrong, there are 36 opportunities (I think) for the session to go wrong. No wonder it takes practice to get it right! For the average handy person, I guess it probably takes more hours of practice to get airbrushing right than learning to drive a car.
But don't get frustrated. Mastering an AB takes time, experiment and practice.
OK. I'm a pessimist. Its what makes me happy because everything turns out better than expected.
