I would avoid any card that charges an annual fee or any card that charges interest on purchases even if you pay the balance in full every month.
That still leaves a lot of cards though so how to chose between them. Well it really depends on how you plan to use the card.
If you plan to clear the bill in full every month then the APRs really don't matter to you. So you should be comparing the perks you can get. There are many different perks (cashback, points in various schemes, low/no fees for foreign transactions etc). Since i'm in the UK i'm not sure exactly what perks are available on the US market and which perks are best for you will depend very much on your situation.
If you want to make a single big purchase and use the card to spread the cost over a year or so then you want a card with a low (ideally zero) initial rate that lasts long enough to clear your big purchase. If you want to make another big purchase later then you probablly want to get a new card at that point.
I would advise against using the same card for both purposes. The best deals for the two purposes are likely to be quite different and it will make it much harder to keep track of things.
I wouldn't worry too much about credit limits. If you are running into them then it probablly means you are buying stuff you can't afford.
Since you say assume complete ignorance of credit cards I feel I have to include a section on what to do once you get it.
In general (there are exceptions such as if your only other alternative is a payday loan or on some travel cards for taking money out abroad) it's a bad idea to take cash out on a credit card. Unlike purchases cash advances will start accrusing interest immediately and there may also be fees associated. At least in the UK cash advances are also reported to credit ratings agencies, I don't know if that is the case in the USA too).
Credit cards will generally charge fees for foreign transactions. You can get these fees down by carefully selecting your card (I know in the UK there is a card available with zero forign transaction fee, I don't know if there is in the USA).
Any borrowing of money requires discipline to avoid making your life worse in the long term. Don't treat a credit card as a license to spend beyond your means.
It may be a good idea to move some of your regular spending to the card to take advantage of perks and to build up your credit history. Again though don't treat this as free money or a license to spend more than you otherwise would.