Pay off your bills or pay way down first! Every payment listed on your credit reports is taken into consideration when applying for a mortgage. You'd be surprised at how much a small payment will lower the amount the bank is willing to finance. I know - I just started the home buying process.
I took advice from many different forums and got a few credit cards in an effort to raise my scores. Sure, my scores have raised over the past 3 months but all it did was hurt me when it came to getting a mortgage loan. A few $10 payments add up and those cost me lots of $$$$ when it came to the amount I could get financed for.
Also, if you can qualify for an FHA loan, don't even worry about credit scores - FHA doesn't consider them. You only need to have no negatives and as few monthly payments as possible.
I could have gotten a much better bang for my buck had I not took a lot of useless advice back when I first started considering a mortgage and the interest rates were much lower.
Now, I have my monthly installment debt lowered. I just consolidated a couple of loans resulting in a much lower payment and my home buying power has now increased substantially. I have all CC's at a zero balance and I'm just waiting on things to report to the CRA's then I'm ready to go forward with my loan so I can buy the house I really want - not ones I currently qualify for but wouldn't be happy with.
My advice is that not all advice is good.