A 100-point jump in six months is realistic if the thing holding you back is fixable fast — high card balances or a recent slip. If your score is already good, gains are smaller. Educational only, not financial advice.
It depends where you start. Someone at 580 with maxed cards has far more room to move than someone at 740. The lower and more fixable your starting point, the faster big gains come.
Credit utilization (balances ÷ limits) is about 30% of your score and moves the fastest. Getting under 30% helps; under 10% helps more. Paying cards down before the statement closes is the single biggest fast mover.
Payment history is ~35% of your score — the largest factor. One 30-day late can drop a good score sharply. Autopay at least the minimum on everything so a slip never happens.
Pull your reports and dispute genuine errors — wrong balances, accounts that aren't yours, a paid collection still showing owed. Corrections can post within a cycle or two and lift your score with no other effort.
Don't close old cards (it shortens history and cuts total limit, raising utilization), and avoid a burst of new-credit applications — each hard inquiry dings you slightly and averages down your account age.
Length of credit history only grows with time — there's no shortcut. Focus your six months on utilization, on-time payments, and error fixes, which are the levers that actually move quickly.