I'm feeling your pain Keith, you're not having a lot of luck, at a formative stage in this hobby! I can imagine that this is very disheartening, and feel it a good idea to suggest a strategy to reel in these issues and set you back on the path!
Firstly, I'd buy a can of Halford's White primer, and find some empty, but clean water bottles, or plastic milk cartons. Give the bottles a covering of primer, prior to shaking the life out of it, and checking the distance they suggest on the can for spraying. When it's had 24 hours to properly harden, mark off a few areas with a hard pencil and start your attempts to get an even coat of
Model Colour on to the areas. For a smooth surface, you want a softish brush, but not one that is floppy (keep those for oil washes!) I did mention a good one in an earlier post, but will repeat it - Winsor & Newton Cotman 666 13 mm - now practice your technique. Try different approaches and pressure. I find, that for the first coat, try to vary the direction of strokes frequently - this will avoid creating a grain. Also, bear in mind that as soon as the paint starts to dry, which with acrylic, can be a really short time, you must stop. The first coat will look awful, the second one won't look too pretty either (!), but have faith and observe how the paint behaves, and you will soon get the "feel", and in no time, you will have made huge leaps in your surface quality! Better to do this with 1 bottle of £2 paint and some empty milk bottles, than have another soul-destroying disaster with your hard earned models. A delicate touch, and nice low angle for those final strokes will give you a surprising result. As long as each subsequent model gets better, you will be on the path to success and, more importantly, satisfaction!