-- Since you're just starting to build credit, I'd keep any line for which you apply and are approved (provided there's no card fee) -- unless the limit assigned is absolutely insulting. Every line you establish and hold onto now will ultimately build your overall credit history - something that's invaluable when you have a "thin" file.
If by chance someone gives you an insulting credit line (say $200, when others are giving you $1000+), I can see immediately closing the account if the card has only limited use and it's not a key creditor with whom you wish to establish yourself. One ultimate factor creditors look at is your average credit line -- low active limits can hurt you. But if it's a creditor who has a reputation for reliably increasing credit lines (such as Citi and BA), then it's worth keeping as an investment.
-- As things stand, I'd be aggressive and apply for both the Target and Hooters card now. I advise applying for them within an hour or two of each other (the shorter the better). If both pull from the same credit bureau, it's unlikely that your second application won't reveal the first credit pull. But if they pull from different credit bureaus, you avoid either seeing another credit line recently established (something that creditors prefer not to be the case).
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Touching on applications you might make down the road: You want to be selective in your credit applications. Each credit inquiry diminishes your prospects for the next application you make.. Therefore, it's important to be disciplined to only apply for credit that will truly be of value to you and, ideally, for which you have realistic prospects of being approved.
-- This means, for example, generally avoiding department store cards that you won't actively use (don't apply to get a one time 10% discount, unless your purchase is large enough to really warrant it). It also means avoiding cards from issuers that others report as being relatively unfriendly -- in terms of customer service, credit line increase consideration, fees, etc. But, as noted, up front you may want to target a couple of cards that are known to be easier approvals, even if you aren't likely to use them much. (This guidance is more directed to those who are inclined to go out and make a dozen applications wholesale, without any regard to potential card benefit.)
-- It also means waiting to apply for cards which have a reputation of requiring strong scores, until you're reasonably confident you match their criteria for approval. Discover is a card that's notable for requiring a 700+ FICO for approval (reported approvals are mixed for 680-700, and negligible for >680). Surprisingly, Sears is similarly strict (even for its store card --- I was turned down with 680).
Bank of America and Chase were most willing to issue credit to me when I was rebuilding my credit after a difficult period of 2 years of repeated delinquencies. Your circumstances differ, your constraint being that you have little established credit history. However, I wouldn't be surprised if they would be more willing to consider you than other issuers.
You can best gauge which creditors are most likely to approve you via discussions on this and other credit groups (such as "creditboards.com"). There are threads here in which people detail credit approvals and scores. Creditboards also maintains a modest self-reported database of similar information. (All advice -- including mine

-- bears a reality check to see if it's really appropriate for you, of course.)
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Ok, I'm running a little rampant with advice and food for thought. Let me address some of the other questions you raise.
-- There's an inclination to think that if you charge up a card to it's limit and repay it with some frequency that this will prompt a creditor to give you a line increase. Sometimes that's true. But I find it's more often not the case. In fact, I sometimes get the feeling that a creditor may fear that if they give you additional credit you might be more inclined to hang yourself with it.
Creditors tend to most value those who show restraint and only charge up most of the line on an exception basis. (And once you establish a few months of strong history on a card, you might go into the store with the intention of making a large purchase and ask on the spot if a credit limit increase (CLI) is possible so that you don't excessively run up your balance against your available line.
So, I advise generally keeping your outstanding balance under 50% of your limit (as you suggest). This has the added benefit of keeping your FICO score strong for other applications. I've seen first hand where running over 70% can cause a serious temporary hit to your score. (Score changes related to balances immediately reverse themselves when you pay the card back down.) Be mindful that most issuers only report your balance to the credit bureaus/reporting agencies (CRA's) when your statement cuts. There's some leeway for your to run up your account between statements prior to your next payment. But don't push the envelope. (A creditor won't look kindly on an account that generally has high utilization - even if statement balances are moderate, and some credit card companies report balances a couple times a month.)
-- The credit options you outline are strong. I think BA should also be on the list for the near horizon. Because they're particularly good when it comes to building credit over time, I think it might be a good idea to establish a secured credit card with them as well. (You might set up the Citi card and try for an unsecured card with BA after 6 mo. If declined, set up a secured BA card.)
-- Just another idea for you. Having 1 or 2 installment loans in your credit history (outstanding or repaid) are good credit builders. Many banks/credit unions will issue a loan secured by savings on deposit (similar to secured credit cards). I've seen credit unions that are willing to lend as little as $500, repaid over 6-12 mo. These can be valuable when you have a "thin" credit file. They're also not a bad savings vehicle. Just try to avoid unusually high interest rates simply because you have little established credit -- the banks have little or no risk.
- Harry