Develop a Sales Journal
When your company has a high sales volume, creating a separate sales journal can cut down on your bookkeeping time substantially. High sales volume is relative, but a good rule when you're first starting out is at least ten sales transactions per day. Once you hit that threshold, trying to enter every sale in your general journal can demand too much of your time — time that could be better spent trying to increase sales.
A classic sales journal is devoted solely to credit sales. This cuts down on the amount of entry work for each transaction while still allowing you to specify the customer involved in the sale. Especially when you work with a manual accounting system, using this special journal will save you lots of time (not to mention helping to protect you from sore wrists and fingers). You can find dedicated sales journals in most office supply stores, or you can create your own if you need some customized columns.
A bare-bones sales journal includes columns for the date, transaction description, and your invoice number, as well as a debit column for accounts receivable, a credit column for sales, and a miscellaneous catchall column. However, if your sales transactions typically involve more than just a debit to accounts receivable and a credit to one general sales account, adding some additional dedicated columns can save you even more time. Extra columns you might want to use include:
Sales tax payable
Different sales accounts (like parts revenue and service revenue)
As soon as you complete a journal page, foot all of your columns (i.e., add up the numbers in each separate column). Then add together the totals of all your debit columns; follow that with a summary total of all the credit columns. For your journal page to be in balance, the total debits must equal the total credits. When the columns balance, it indicates that your entries were recorded correctly.
Cash sales are generally recorded in one daily lump in a separate special journal called the cash receipts journal. When you have mainly cash sales, peppered with just a couple of credit sales, you can use a combination sales and cash receipts journal.