-Try to avoid Paypal when possible. A real merchant account will give you better rates, and slightly better protection from charge backs (you'll be dealing with only the Visa/Mastercard chargeback rules, and not Paypal's own rules on top of the credit card company rules)
-When you do use it, take the money out of the paypal account and into you bank account as soon as possible
-Have a bank account dedicated for paypal. Only use it to withdraw money from paypal. As soon as it gets deposited to your bank account, transfer it to one of your regular bank accounts. (Paypal can reverse transactions and take money from your bank account, so be careful what account you give them access to.)
-Have back up merchant accounts to use so you're still able to accept credit card payments when your paypal account gets frozen. Paypal might only put a temp freeze on your account, but this way you're not scrambling looking for an alternative merchant account. I like Stripe, but there is lots of choice now.
