For freelancers, consultants, actors and other self employed people, life gets complicated this time of year. Digging around for the paperwork to fill out tax forms practically qualifies as exercise.

"They have a nightmare trying to find receipts," said accountant Tristan Zier.

Zier founded Zen99 to help freelancers manage their finances, including filing their taxes.  His most important advice to freelancers: keep track expenses and receipts year round rather than pursuing a paper chase as April 15 nears.  

"When they can’t find receipts, they can’t write off their expenses," he said. "And they’re paying more money to the government instead of keeping it for themselves."

Zier and others have come up with a lists of common mistakes freelancers make at tax time. 

Here are seven don't - or, deadly sins, for freelances at tax time:

1. Not knowing what they owe.  Zier says there are 20 different 1099 forms that get sent out to workers to track freelance gigs.  One of them is the 1099-K, which only has to be sent to you by a company in paper form if you make over $20,000. "People think, 'Great, no paper form, no taxes on that," says Zier. "Big mistake there.  You still have to self-report the income."   
2. Not knowing WHEN they owe.  For freelancers who owe more than $1,000 in taxes for a year, tax time comes more often than just April 15.  They have to pay taxes quarterly. But then it's not coming out of paychecks like it does for permanent employees. 

3.  Not tracking and writing off the right types of business expenses. Zier says many freelancers fail to realize they can write off part of their cell phone bill as a business expense.  Expenses vary by the type of work.  "A rideshare driver's biggest expense will be related to their car, while a web developer's biggest expense might be their home office," Zier says. "Figuring out what expenses are important to your type of work is important is maximizing your tax savings."

4. Writing off personal expenses.  This goes back to that cell phone.  If you use the same phone for personal and business purposes, don't be tempted to write the whole bill off. Estimate the amount you use it for your work. The same goes for your vehicle. Don't go trying to write off miles driven to the beach. 

5. The Double No-No: counting expenses twice.  Speaking of vehicles, Zier says most people use the Standard Mileage Rate ($0.56/mile for 2014), which factors in gas, repairs and maintenance and other costs like insurance and depreciation. But if you use this rate, you can't also expense your gas receipts and repair bills.  

6. Employee AND employer.  At lifeofthefreelancer.com, financial consultant Brendon Reimer reminds freelancers they play both roles. For regular employees, Federal, State, and payroll taxes are withheld from a paycheck, and distributed on the employee’s behalf. It's how Social Security and Medicare are funded. The IRS mandates that the employer must pay half of every employee’s payroll tax, and the employee is responsible for the other half.  Independent contractors have to handle both halves.  "The IRS does give you a small benefit by letting you deduct the half that you pay yourself as a business expense," Reimer writes. Zier said the freelancer's sin here is believing he or she pays more taxes than the regular working stiff.  

7. Not keeping adequate records. The IRS requires you to keep proof of all business receipts, mileage, etc.  If you can't show these, the IRS  could refute the expense and force you to pay back taxes. Zier says the good news is there are other ways to prove expenses if you've lost the receipt. A bank or credit card statement with the date and location might do the trick. "The IRS is surprisingly accommodating if you are doing your best," Zier says. "If you're being a headache, they're going to be a headache as well." 

In separate reports, Zen99 and the consumer finance web site nerdwallet ranked Los Angeles the best city for freelancers.

Each considered housing and health care costs, the percentage of freelancers in an area as factors. Zier said even before the sharing economy began to take off, the entertainment industry and growing tech scene were already strong sources of freelance gigs in L.A.

"Even back in 2012, L.A. had twelve percent of people report themselves as self-employed on the Census," Ziers said.   "You know your Ubers and companies like that  are really bringing a lot of attention to the contractor market, but it was a very robust community before."