Almost everyone starts by buying too much and working too big. A twenty-four color set, a stack of large canvases, a dozen brushes, and then a first painting that goes badly enough to end the experiment. The list below is the opposite approach: less equipment, smaller surfaces, and a clear idea of what you are practicing each time.
1. Pick one medium and stay with it

Acrylic, unless you have a reason to choose otherwise. Water cleanup, no solvents, dries fast, and opaque enough that a mistake is fixed by waiting and painting over it. Give it six months before you try anything else. Switching mediums every few weeks means restarting the learning curve each time.
2. Six colors, not twenty-four
A warm and a cool version of each primary, plus a large tube of white. That mixes nearly everything, and mixing is the skill. A big pre-mixed set teaches you to hunt for the nearest tube instead, which is why paintings made from them tend to look the same as each other.
Skip black at the start. Darks mixed from a deep blue and a brown are richer than tube black, which flattens everything it touches. The color wheel explains which pairs do what.
3. Three brushes
A medium flat for covering ground, a small round for general work, and a detail round for the fine passages. Buy decent synthetics rather than a bargain pack of twelve. More brushes than this is not useful until you know what you are missing, and there is more on choosing them in our guide to brushes for acrylic painting.
4. Work small
8x10 at most, and 5x7 is better. A small painting is finished in an evening, which means you complete twenty of them in the time one large canvas takes. Twenty finished paintings teach vastly more than one, and the stakes on each are low enough that you will actually experiment.
5. Get the values right before you worry about color
Paint three or four studies in white plus one dark color only. It is a dull exercise and it is the one that separates paintings that read from paintings that do not. Nearly every beginner painting that feels wrong is wrong in its lights and darks rather than its hues.
6. Prime the surface
Paint sinks into raw canvas or paper and dries dull and patchy. Most canvases sold today are already primed, but boards and paper often are not. A coat or two of gesso costs almost nothing and changes how the paint sits.
7. Two water jars
One for the first dirty rinse, one for the final clean rinse. This single change does more for the clarity of your color than better paint would. Muddy color is almost always a dirty brush rather than a mixing error.
8. Keep the paint workable
Acrylic on an open plate is unusable within twenty minutes. A stay-wet palette — a shallow tray with damp paper under baking parchment, or a purpose-made one — keeps a session going and stops you throwing away half of what you squeezed out.
9. Paint from your own reference
From life if you can, from a photograph you took if you cannot. Copying somebody else's finished painting teaches you to reproduce their decisions without ever learning why they made them. A pear on your own kitchen table teaches more than a copied landscape.
10. Fix rather than restart
Acrylic covers itself completely once dry. The instinct to abandon a painting the moment something goes wrong is the single biggest brake on getting better. Let it dry, paint over the bad passage, and carry on. You will learn more from rescuing one painting than from starting five.
11. Paint the same subject three times
Not because the third will be better, though it will be. Because by the third attempt you stop thinking about what the object is and start thinking about how to paint it, which is the shift the whole thing depends on.
What to ignore for now
Palette knives, mediums, gels, texture pastes, varnish, and expensive surfaces. All of them are useful eventually and none of them will make a beginner painting better. The same goes for large canvases, which mostly serve to make a difficult thing bigger.
If the blank surface is the obstacle
A lot of people who want to paint are not stuck on the paint at all. They are stuck at the start, staring at white canvas with no idea where anything goes. That is a real barrier and it is worth naming rather than pushing through.
Watching somebody build a painting from nothing helps, which is what the free channels in our roundup of acrylic tutorials do well. So does working on a canvas where the drawing is already done, which is what a numbered canvas is. Either way, the brush handling you build carries straight over to painting something of your own.