Sticking to your budget will help you manage credit. Credit application forms are all the same - you've read one, you've read them all. Credit rates rise and fall with interest rates. Credit makes impulse buying much easier, and more dangerous. A poor credit rating can make it hard to lease an apartment or even a computer.
All credit cards are pretty much the same.
The more credit I get the better my credit rating is. Credit is still money, so you should compare price and value when you're shopping with credit. Increasing your down payment will lower the cost of your loan in the long run.