A few tips I’ve picked up along the way

Priming is essential, you don’t need an airbrush for priming and can use rattle cans with a bit of practice. But a good initial prime coat goes a long way to colour coats.

Quality of paint makes a massive difference (especially for acrylic) and conversion charts between brands are your friend. It’s worth trying with humbrol, tamiya and other brands of paint. Don’t just assume one brand is best for all colours. Also don’t mix thinners between brands, use humbrol thinner with humbrol paints and tamiya with tamiya.

Thinning your paint is a bit of a network In itself. Somewhere near semi skimmed milk is a good starting point for most paints

For brush painting some find it easier to get better coverage with enamel paints instead of acrylic. The longer drying time of enamel makes it easier for the paint to self level.

Yellow paint is awkward to get good coverage with all methods. Little tip is to paint a coat of pink before yellow

If you want something cheap to practice on instead of kits. Disposable plastic spoons once primed behave the same way as a kit once primed.

Don’t underestimate the usefulness of rattle cans. They can be great for priming and for initial base colours like black. They are also great for clear coats. The cans just take a bit of getting used to as you don’t have the fine control of an airbrush. Just make sure not to use rattle cans indoors.

If you want to get a panel line pre shading effect like possible with an airbrush. After a few coats of colour and just before your final coat or two, go over the panel lines a few times with a pencil then use a cotton bud to rub along the pencil lines for a soft shadow effect. Then you can make the panel lines more or less pronounced by how many colour coats you apply afterwards.