just a check in 16 or so months later. building credit has gone really well, capital one have repeatedly increased my limit and it's now at 700 bucks. i also successfully bought a bed on credit - exciting, i know. also been working at apple for almost a year now, so all is going well
Congrats! Responsible use of credit is SO important in a person's life (and surprisingly goes almost entirely untouched/undiscussed in high school).
I am a loan underwriter at a credit union. I look at credit reports all day, every day.
I'll echo a couple things that have been mentioned here already.
The most important thing with credit cards - pay them on time! Late payments are extremely detrimental to your credit.
As a rule of thumb, utilize 30% or less of your available credit. So if you have a card with a $1,000 limit, only carry a balance of $300 or less.
One card with a larger balance is better than a bunch of cards with smaller balances. For example, it is better to have a card with a $5,000 limit and a $1000 balance, rather than four smaller cards with $250 balances on each one.
Age of accounts is important. The longer you have an account open and maintain positive payment history, the better it is for your credit.
Credit mix is important. It is good to have a mix of credit cards and installment loans (car loan, mortgage, student loans, etc.).
Take is easy on the credit inquiries. Every time a creditor pulls your credit in order to open up a new account, your score gets adversely effected. However, if your credit is pulled multiple time within a 30 day period for the same purpose, it only counts as one inquiry against your score. For example, if you're shopping around for a car or mortgage and 3 different companies pull your credit so you can compare interest rates, you should only be "hit" for one inquiry against your score (even though all of the inquiries will show on your report). It should be noted that credit inquiries aren't as detrimental as some people think. You're only docked a couple points for each unique inquiry. Also, some companies (usually cell phone providers, utility companies, some credit card companies when they're doing limit increases) will do "light pulls" on your credit, which do not impact your score at all.