We all make mistakes. We miss marketing opportunities, we take on bad clients, and we ship less-than-great projects. The trick is to find and fix these mistakes before they become habits.

Here are 11 common mistakes that can make a huge impact on your time, your income, and your sanity:

1. Setting your rates too low.

Are you charging what an employee at your skill level would get per hour? Do you price low because you’re worried that the $10/hour freelancer on Craigslist is going to undercut your rates?

You’re not doing it right. Many freelancers fall into this trap.

Here’s how to actually charge what you’re worth. You’re better than that $10-for-5000-words guy on Craigslist; show the client that you are with professionalism and a solid portfolio and website.

2. Not researching your clients.

You got an answer back to your pitch! You got an @mention from a prospective client on Twitter! They’re offering OK pay and you jump right in.

There are many stiffed, unhappy, abused freelancers in this world -- don’t add your name to the list. Don’t just rely on what the client says about themselves, do your homework. Ask them questions. Here’s exactly what to look for.

3. Not putting enough aside for taxes.

New freelancers are often shocked at how much Uncle Sam takes from self-employment income, and unfortunately haven’t saved enough to pay the bill. This can happen to veteran freelancers too, especially if they’ve been hit with a dry spell.

While not the end of the world (there are ways to manage your payments over a long period), it’s not the kind of situation you want to get into. While a bit annoying, paying taxes quarterly actually does help make this process more manageable. Learn how to file quarterly taxes and estimate payments here.

4. Forgetting to ask for recommendations and referrals.

Embarrassed to ask for referrals on LinkedIn or recommendations for your website? You’re missing out on one of the most effective, totally free marketing tools for your business.

We’ve broken down exactly how to reach out to past clients in an unsleazy way that gets you the kind of referral you want here. Remember: even if you don’t use them now, they’re good to have. If you do it right, it shouldn’t take your client more than 5 minutes.

5. Getting stuck in a gig rut.

Your freelance career will evolve. Your interests change, your field changes. But sometimes you can feel like if your business is going well, you don’t want to branch out, try something new, or venture into a new field -- it just seems to risky. On the other hand, freelancers in a dry spell may just plug away trying to find work in their field and not expand their horizons to think of other revenue streams that can keep them going.

Try these alternate revenue streams perfect for freelancers. We’ve also talked in depth about three of the most common side gigs: selling physical products (prints, t-shirts, etc.), teaching online, and writing an e-book.

6. Not saying “no.”

Do you know your freelance rights? Don’t get into a working relationship with a client without setting clear boundaries. Remember that you have more power than you realize, you just need to communicate clearly.

Many freelancers also don’t say “no” to new gigs -- even if they’re not a good fit. As freelancer Sean McCabe explains here, selectivity about clients is one of the best things you can do for your business, even if you think you can’t afford to be selective.

7. Not keeping track of receipts.

Yes, keeping track of receipts is annoying. But when you’re looking at your tax deductions for the year, you’ll be grateful you kept track. We found some easy apps to keep track of receipts here.

8. Not having a contract or not looking at the contract a client sends.

If you don’t draw up a contract, you are playing with fire. It’s just a TERRIBLE IDEA, please don’t do it.

That said, even freelancers who do use contracts sometimes don’t understand important contract provisions or think that the client will expect you to just accept all the terms in the contract. Most lawyers create a “dream contract” for big companies that they are willing to negotiate on. Stand up for yourself and you’ll actual earn more respect as a freelance professional.

9. Not understanding Intellectual Property rights.

Do you know the laws around Intellectual Property and client work? Do you know that all IP is yours -- even if you sign a contract -- if that contract doesn’t transfer IP rights to the client? Do you understand how valuable retaining IP rights on your client work can be?

This is one of the most overlooked topics for freelancers. You could be leaving money in the dust! Learn about your rights here.

10. Not following up with previous clients.

Repeat clients are the best clients. Don’t sit on your contact list of previous clients or wait for them to remember you exist. Send them friendly, non-markety emails checking in with them, or better yet, include them on an email newsletter list to receive your bi-weekly email chock-full of industry tips.

11. Avoiding connecting with and helping other freelancers.

It’s surprising how many freelancers assume that networking with other freelancers isn’t valuable. Networking within your industry is helpful, but don’t avoid other freelancers at the event. Connecting with other freelancers can mean gigs, industry insider news, and even business partnerships. Here are more than a dozen ways freelancers can help one another.

Looking for other freelance tips? Join Freelancers Union today to gain access to even more great content.