Pay every bill on time — it's 35% of your score
Payment history is the single biggest factor. One 30-day late payment can cost a healthy score 60–100 points and stays for seven years. Automate at least the minimum on every account so a busy month never becomes a late mark.
If you already have a late payment, going forward on time is what rebuilds trust — and the older the late mark gets, the less it weighs.

Lower your utilization — the fastest lever
Utilization (balances ÷ limits) is about 30% of your score and updates every month, so it's the quickest win. Aim to keep it under 30%, and under 10% is better. Paying a card down before the statement closes can jump your score within one cycle.
Two tricks: pay mid-cycle so a lower balance reports, or ask for a credit-limit increase (which lowers utilization without paying anything, as long as you don't spend more).
Keep old accounts open
Length of credit history is about 15% of your score. Closing your oldest card shortens your history and can raise utilization. Keep old no-fee cards open and use them lightly once in a while so the issuer doesn't close them.
Be selective about new credit
New applications create hard inquiries (about 10% of your score) and lower your average account age. Space out applications, and only apply for credit you actually need.
Myths to skip: carrying a balance 'to build credit' (false — it just costs interest), and closing cards to 'clean up' your report (usually backfires).
There's no button that raises a score overnight, and anyone promising a guaranteed jump is selling something. Subefy builds a prioritized plan from your real report and simulates what each move could do. Results vary; no specific increase is guaranteed.