Note that you will almost certainly not be able to get any kind of credit card in Thailand - they simply don't extend credit to foreigners.
If you need actual CREDIT, then right, you're going to have a rough time. However, I think pretty near all ATM cards from Thailand banks have a VISA account attached to them. It's not actual credit, but it's a VISA card, and the money is just instantly taken out of your checking account.
Anyway, a few extra if anyone cares:
Culture Shock -- Prepare yourself for this one. I've lived in various countries, and without question, Thailand was the hardest one to deal with in terms of culture shock. Took me about 2 years, but I'm extremely glad I'm still here, because now that I'm 100% comfortable here, there's no way I would trade this life for some luxury condo in some metropolis again.
Obviously, it depends how you live though. If you live in some luxury condo downtown BKK, and spend all your time at Western megamalls, steak houses, Irish pubs, and Starbucks, it obviously won't be very difficult. If you integrate yourself into a Thai neighborhood & society though, and live with other Thais in your house / condo, you can expect some culture shock. And remember, culture shock comes in phases over a long period.
Privacy -- Depends where you live I guess, but if you're in a place without many foreigners, expect to have almost zero privacy. Expect everyone within a 5km radius to know who you are, where you live, who you live with, what you eat, what you drink, if you fart when you shit, what you wear, how often you sleep, and so on. It can take some getting used to, but once you're used to it, it's great, or at least I enjoy it. Everyone knows each other, you see each other several times a day, everyone gets along and helps each other out as needed, etc.
No Fighting! -- Never fight with a Thai. Just don't do it. If you end up in an altercation, it doesn't matter who's right, just respectfully back down. Trust me.
Don't get angry -- There's just no point. For example, if you're angry at some store, the internet provider, your landlord, or whatever, keep your mouth shut, and don't bother expressing it. If you do, it's going to fall on deaf ears, nobody is going to give a shit you're angry, and it's going to make it 10 times harder to get anything done. Just relax, take it as it comes, and don't worry about it. Flirt with the cute girl in the store instead of yelling. It'll work.
Prejudices -- This is a pain, and one you'll always have to deal with. If you have white skin, everyone knows you shit bricks of money, and millions of dollars just magically appear for you every time you sleep. So when meeting new people, you constantly have to listen to whiny assholes go off about how poor and hard done by they are. However, once people actually get to know you, and get past the fact you have white skin, they're great.
Learn Thai -- Just go learn it. A whole new world opens up for you. Not to mention, you'll gain immediate respect when meeting new people. Don't ever learn using the transliterations you see in books though, because you'll end up talking like a retard, and nobody will understand you. Learn just as if you were 3 years old. Alphabet first, have a Thai sit with you and ensure you're pronouncing each character properly, then move into words, reading, writing, etc. If anyone wants, I have a few movies (Inception, Limitless, Avatar, etc.) that are in Thai, with both Thai and English sub-titles on at the same time. Works great for helping learn!