One of the easiest ways to screw up your business accounting and possibly run afoul of the IRS is to commingle personal and business funds. Using a business account for all business transactions eliminates that possibility.
Get a business account using your business name and EIN Number, and only use that account for all business-related deposits, withdrawals, and transactions.
Pick a bank or credit union that is convenient. Check out your local credit unions; often they provide better deals than commercial banks.