How Much is Too Much?

30% of your FICO score is made up by the amount you owe on each credit line.
When you review your credit report you need to look at a few different things.
First off, how close to your credit limits are you?  If you have a lot of credit cards and are only using one and you've spent almost 80% of your available credit limit that will hurt you just as much as if you have 3 credit cards and all of them are near their capacity.
Next how much total credit do you have available to you?  Do you have several thousand dollars?  Only a few hundred?  Nothing?  Add up all of your credit limits then figure out how much you have available to you and that will tell you how much you have available.  This number is used to determine your debt to income ratio and is a very important number when it comes to applying for loans.  I'll get into that later but it's also super important when figuring out your FICO score.
Third, how much revolving credit verses installment loan debt do you have?  Revolving debt is anything open ended such as credit cards, lines of credit, anything that allows you to continue borrowing off the available balance.  Installment debt is anything that's closed ended, like an auto or personal loan, mortgage or a student loan.  In most cases you must pay a certain amount each month for a fixed term at a fixed rate.
And lastly, you must be aware that your account balance on your credit report will most likely be your statement balance.  So even if you pay off your credit card every month it will most likely not show $0.  This can hurt you if you pay everything with a credit card every month.  If your balance is high in relation to your limit it's going to lower your FICO score.
I always recommend to people that they should make sure they keep their limits high and their balances low and pay them off every month.  If you are unable to do this then you may need to rethink your budget and how you spend your money.  Easier said than done sometimes, but it's something to keep in mind if you ever want or need to take out a loan.