How do I actually become more confident?

The pages behind this answer share a starting objection to just be confident; the first of them says it hands you the outcome as the method. Each replaces it with something you can do tomorrow.

Pick one thing and get good at it. Confidence follows competence says there is no confidence in general to work on. There is confidence at the piano, which comes from playing until you cannot get it wrong; confidence in the gym, from being someone who knows what they are doing in a gym; confidence at your job, from being good at your job. Each is built separately and none transfers as cleanly as people expect. Someone who worked with trial lawyers described the illusion from backstage: in court they look like geniuses, and the secret is months, ten-hour days, every brief checked four times, openings written, practised, thrown out and rewritten. What reads as a personality is usually preparation you were not in the room for. One person there landed the sequence: get capable, and you start to see yourself as capable, and the confidence arrives behind that, as what is left over.

Act while scared; the confidence is the receipt. Confidence is the receipt, not the ticket says almost everybody has the order backwards. It looks like confident people are confident first and act second, so you wait to feel ready and the waiting becomes the year. What you need up front is not confidence but courage, a smaller and more available thing, because courage is compatible with being scared. One person emigrated alone, terrified, and did it frightened, and it worked. Another, still in bed an hour past the alarm, typing lying down, got up mid-sentence to leave the phone by the basin and wash their face, and wanted whoever wrote it to know that it works at tiny sizes too. What people bring back from the other side is not fearlessness but that the thing turned out smaller than the rehearsal, and that they now had one instance the next attempt could stand on. You are allowed to be unconfident and go anyway.

Buy repetitions. Familiarity starves fear is the mechanism under every do-it-scared tip: fear runs on the unfamiliar and thins as things become known, so the cure is repetition rather than courage. The moment it landed for one person there: they had assumed confidence was something a person either had or did not, and seeing it as something exposure builds reorganised the question. They were not short of a quality; they were short of repetitions, which can be bought with time at whatever size you can afford. The first time is expensive and buys you the second time cheaper, so book the second one before the first has happened.

Keep one promise you cannot lose. Small promises you actually keep treats confidence as a ledger: every promise kept to yourself is evidence and every one broken is also evidence, and you were the witness that counts. Make a promise small enough that you cannot fail it, making the bed every day for a week, ten pages, one fixed wake-up time, and keep it. Confidence built out of encouragement evaporates on contact with a bad week; confidence built out of your own record does not. That page is careful about what this buys: self-trust, not self-worth, and it draws the line between them. Expecting to do well at a thing is confidence; being all right regardless of how it goes is self-esteem.

Who this is not for. The last page adds the note this answer keeps: hardly anybody was born short of confidence, and what an injury took does not always come back through discipline. If the thing underneath turns out not to be a shortage of follow-through, believe that too. The page Unlearning the verdict, cited here, says most confidence advice is addition and the useful work runs the other way: what comes out is a settled background belief that something is permanently wrong with you, and its target is a neutral view, not a flattering one.