Best ways to fix a low credit score? ?

Pay every month before the due date.

Pay more than the minimum even if its only a couple of bucks.

Don't cancel cards when you pay off the balance.

As you pay down debt don't take on more debt elsewhere.

Do not make more than two credit apps per year.

Concentrate hard on getting at least one bill paid in full asap.

Pay all of your bills on time, every time for a long time.  

Get your credit reports and see WHY it's low. If it's not paying on time, then start paying on time--if it's carrying too much debt for your income level, then start paying down the debt by making MORE than your minimum payments. If it's bankruptcy, or collections, then get those collections paid, and just wait on the bankruptcy--because that stays on your report for a long long time. (ten years or more). 

The best way is not to open other credit accounts, don't take out loans, don't try to live on money you don't really have and get your bills paid. It will not happen overnight. 

Pay off your debts and then start paying under contract - ON TIME and at least the minimal amount due.

pay your bills ........

Prove that you can pay what you owe on time according to contract.  That means:

You need to be carrying some reasonable level of debt for a long period.

Show that you can faithfully pay off some and not all of that debt according to plan.

My score is currently over 830, but a bit over a year ago it dipped below 800 when I made a big purchase ($30K) by credit card.  The scorers felt that $30K was not a reasonable level of debt it seems.

But within a matter of months, my score was again above 800.  Why?  Because I paid off that $30K that I owed.  Apparently $30K was not an unreasonable debt load after all for me.

Pay off the debts you have and make on time payments on all your existing credit accounts. There is no fast fix, everything will take time.

Pay the debts you have and don't build others up.