Here's a few ways to increase your credit score quickly:
1. Use credit cards, so you have credit to improve upon.
2. Reduce your expense ratio by paying your debts off twice a month (one auto pay, and pay once manually).
3. Reduce your expense ratio further by having your credit card increase your credit limit (obviously, spend the same as you would each month, or less if possible).
The 3 methods above boosted my score quite rapidly within a span of a few months.
I think there's some credit score threshold guidelines to purchase a house. But you don't want to buy a house just as soon as you *can*. This is because you'll get bad financing. It's preferable to wait an extra 3-6 months and get it over 750 or something so you can pay a lot less for the mortgage over a 30y timeframe.