Hi JunieB!
Nehis is absolutely right. The All Zero Except One (AZEO) approach helps you squeeze out extra scoring points in the 1-2 months before an important credit application (e.g. home loan, auto loan, difficult to get credit card, etc.).
It does not help you as a long term strategy for gradually building your score over time. The strategy there is to be doing all of the following:
* Always pay on time
* Once you have plenty of accounts, avoid applying for more.
* Keep utilization reasonably low (just so your creditors don't get worried). 1-29% is fine. So is going a bit higher sometimes.
* Try to have an open installment loan that is mostly paid off. If you have a car or a home loan, the "mostly paid off" thing is not easy and shouldn't be worried about. But otherwise this piece is easy to meet -- ask people here if you need more info.
A final key item for the future is to always pay your cards in full. This is called being a transactor and future scoring models will like that a lot. If you haven't been doing that for a while, it will take a while to create a history of this inside your report, so you should get started on it soon.
