Originally Posted by deltame

OP, you call yourself a newbie, so I suggest the following: if your credit history is short then it does not hurt to wait for a while (at least until you get comfortable) before applying for other credit card(s). Use this time to
(1) study the threads in this forum (and miles buzz forum), not just for best sign-on bonus cards alone but also understand you could target separate credit cards for sign-on bonus, credit cards to put spend on, and credit cards to keep b/c certain benefits (that you can use)
(2) get a better idea on your spending habits (categories and amount of regular spend that you can put on credit cards)
(3) clarify your travel preferences (e.g., coach or business/first class air travel, domestic or international, budget or comfort or high end hotel etc.)
(4) devise one or two travel goals (destination, departure city/airline preference if any, etc.)
The credit card offers will be there (at least the UA mileage explorer card offer will still be around, say for the next 3-6 months) when you are ready. If you anticipate significant credit card spend in the next few months, then I would consider jump start the process and do a quick study to get ready; otherwise take your time to learn and become knowledgeable (at least towards self-insight w.r.t. what you want to accomplish).