I've been a freelancer for many years and actively coached and helped a pile of freelancers from every industry imaginable to grow their businesses. I have come across the same business blunders time and time again, enough for me to draw the conclusion that the following list really does make up the 9 biggest, most costly and sadly the most common freelancer mistakes.

Of course any freelancer who manages to avoid making these mistakes and in fact does the opposite, will build a fantastic business, charging what they deserve to be charging and with a long list of valued clients.

So what are the 9 biggest and most costly mistakes that freelancers make?

1. They have a confusing offering.

In other words it is really hard for potential clients to figure what services they are providing and what problems they will be able to solve. Being able to sell yourself and what you do is vital to the long-term success of any freelance business. Often the client doesn't really know what they need, but they know that they need a particular freelancer to help them, so make it easy for them to buy the services you are offering.

2. They are poor communicators, with clients continually having to chase the freelancer.

This is normally the biggest complaint made against freelancers--they are lousy communicators. If you want to build a really successful business as a freelancer, become exceptional at following up. Get back to people before they expect you to, even if you have nothing to update them about.

3. They don't differentiate themselves in any way from their competitors.

In fact it is even worse, they tend to tell their potential clients how they are exactly the same as their competitors. Check out a range of freelancers from the same niche and you will find that they list all of the things they do (like accountants who say they do tax and provide business advice--imagine that?)--as opposed to explaining what makes them significantly different.

4. They are reactive to business development not proactive.

They wait for business to come to them as opposed to chasing it, or even working with existing clients to develop more business over a longer period of time. Business development tends to be done based on need (as in "quick we need more work") as opposed to a strategic business development plan.

5. They are lousy at asking for referrals.

Often freelancers are very reluctant to ask their clients to refer them. Feedback that I've had is that it feels a bit pushy and too much like a sales person. Well I hate to break the bad news but if you aren't selling you aren't eating. Freelancers who do a great job should never be afraid to ask for referrals, and they will get them naturally anyway.

6. They bill without showing details leading to client dissatisfaction.

I remember a few years back I received a bill from my lawyer--it had a one-line description, "Legal services rendered $25,000". There was no description, no explanation, certainly no sense of value. It just looked like a number was plucked out of thin air. You have to provide itemized and detailed invoices, explaining exactly what you did, including anything you did for free. Show value for money.

7. The client gets fobbed off to lower level staff.

This is typical in a growing business. In the early stages you get the full attention of the business owner, but over time, you get passed onto someone else and you feel less valued and important. Not long after this, you change freelancers. There is nothing wrong with getting other members of your team to manage a client's work, but explain to the client how it will work and make sure they are OK with it. Stay in touch with them and make sure they know that you are always available to them if they need you.

8. They provide bad advice, more as a lack of attention to detail than anything else.

This tends to be a problem in a business that has really taken off and the freelancer is holding a tiger by the tail, just trying to get through their huge workload on a daily basis. They don't pay attention to the details simply because they don't have the time. Their service suffers, which clients will deal with for a while, but when the advice suffers, the situation becomes unacceptable. As freelancers we need to manage our own workloads closely and be honest enough to know when we are slipping and smart enough to do something about it immediately.

9. They don't manage their client relationships.

When the client stops feeling that loving feeling with their freelancer they move on. Smart freelancers always build and maintain their client relationships, in fact it becomes the backbone of their marketing activity. They communicate, they are proactive with the advice they offer and they acknowledge the relationship and the fact that they value it.