It should be obvious, but it's a detail that far too many small business owners tend to overlook – if you want to make money, you need to make sure your clients pay you. Proper invoicing skills are needed to ensure that your business keeps the cash flowing in a timely manner.

There are no words more beautiful to an entrepreneur than "Your check is in the mail." Here are a few financial tips that will help you with billing your clients.

Accurate documentation is crucial
Be extremely careful when writing bills to send to clients. One small typo can torpedo everything, as notes, so you need to make sure that names, addresses, payment amounts and due dates are all delineated perfectly. Each invoice should describe clearly and accurately what the client is being billed for, and multiple invoices should be numbered in order so you can easily track the sequence of payments.

Know your customers
If you're bothered by cash flow problems and you can't figure out what happened to that outstanding few dollars, it helps to be aware of your clients' payment patterns. Does this one usually send money on Fridays? Does that one wait until the end of the month? Who pays out large lump sums immediately, and who makes slower, more gradual payments? Knowing your debtors' tendencies will help you keep tabs on where your money is.

Keep in touch
If you ever have any doubts about a particular payment, it's OK to place a polite phone call or email to the client to check up on them. Keep things light and friendly – you don't want to sound confrontational, lest you alienate them and lose business. But if someone's payment patterns begin to stray from the norm, it couldn't hurt to ask.

Consider e-invoices
It's high time that small businesses begin to look into online invoicing solutions. According to The Maritime Executive, there are potential savings of between 50 and 80 percent to be gained by sending invoices online. Packaging and postage aren't cheap, and there's also the added convenience. Billentis reports that e-invoicing grew by 20 percent last year, which is nothing to sneeze at.

If you want your small business to rake in the big bucks, you've got to send out a bill and ask for that money. With accurate invoicing and innovative business banking solutions, you can keep the cash flowing for your business.