Yes, it's that simple! You can negotiate a lower rate by calling your credit card company or loan lender. With this method, most people who try are successful.
The more ammo you have ready before picking up the phone, the better. When it is finally time to call, remember: being polite is key to being able to lower your interest rates.
A balance transfer card lets you consolidate your credit card debt. This is better if you're accruing interest on multiple cards since you can put it all on one account.