Invoicing
In order to get paid, you need to let your clients know how much they owe you, and why. Unlike a 9-5 job, where the steady paycheck comes at the end of each month, being a freelance worker means keeping track of exactly how many hours you have worked, at what rate per hour, and for whom. At the end of each job, you need to send the bill out to the client, and make sure you get what you're owed.
Record Keeping
When you first take on a job, and give your client the quote, you should try and work out exactly how many hours the job will take you. A lot of this is a matter of experience, and once you get settled into your job, you should be able to figure out pretty accurately the number of hours multiplied by the hourly rate. When you send in the invoice, you need to include a careful breakdown of exactly how many hours were worked.
This is where you need to keep an accurate clock in the office or use a suitable timekeeping program. Very often these work automatically with an Excel spreadsheet or similar accounting software to record what you did when.
If you can simply copy and paste a spreadsheet when it comes to the final billing, you will save yourself valuable time. If possible, it helps to further breakdown the job into constituent parts, with how many hours were worked on each segment. This will not only make you appear more professional, but will limit your clients capacity to argue with the final amount.
The Invoice
Invoice templates are available in Microsoft Office, or you can always download them from the internet. Your invoice should be sent as an email attachment, preferably alongside the email detailing the work's completion. With some clients you may need to send a hard copy invoice as well.
Your invoice should be clearly labeled, with the exact job as the heading, and subtitles dividing the work into its constituent parts. A grand total should appear at the bottom. With your address and contact details on the bottom of the invoice, your client will have no excuse not to pay on time.
You then need to detail when you expect payment as well as different methods of payment. Sending a check is perhaps the easiest way for your client to pay you, but you may prefer PayPal, or even an ACH (automated clearing house) transfer.
Calling after a week to ask if your client received the invoice, if nothing has been heard, is a good idea. You should also keep track of which clients are reliable, so that you know who to work for again. If you work regularly for the same clients you may also wish to send them monthly statements.
Getting Paid On Time
Making sure that you get paid, and on time, is one of the most important things to get right when running a freelance business. You need to set aside time at the end of each working day to ensure that every hour you worked has been logged, so that you can get paid for it later.
In an ideal world, your client will pay immediately upon receiving your invoice. Of course, in real life, late payments, or even non-payments are sadly real risks for the freelancer, and you will have to expect this to happen every once in a while. But with proper invoicing, and careful monitoring of clients and your own working hours you should be able to keep this to a minimum.