Not putting away money for taxes
Nearly 80% of people starting a new business, forget to set aside money for taxes at the end of the year. When they don't do this, they end up owing money to the IRS, that they don't have in the bank.

Ignoring Customer Feedback
A lot of your continuing success is actually listening to Feedback, especially from current clients/customers. Most people think their way is always the right way and are closed off to comments or criticism. Take consideration of what others are saying, it can improve your skills and garner more clients in the future.

Not getting Business Insurance
If you're renting a location, you may already know that you need to have Liability Insurance, but people often overlook insurance when working out of their home. If you have inventory for your business, you'll want to protect it, in case something wipes out your inventory.

Failing to separate Business Assets from Personal Assets
This is where having separate bank accounts for your Business and Personal are key. You don't want to intermingle the two or it can have in impact on your spending and tax implications.

Forgetting to Market or Advertise
Finding customers or clients can be the biggest challenge you face in order to make your business a success. You need to have some type of presence, whether it's a website, social media, or word of mouth. How else will someone even know you're around?

Trying to do it all yourself
When starting your business, you more than likely aready have an idea of how your product works, or your service will be handled. But there will be times where you may be out of your realm. Don't be afraid to ask for assistance. You can find many resources online if you're stuck on a problem. If you have to go a step further, you may have to hire someone either on payroll or as a consultant. Just ask yourself first, "Will this move my business forward?", or "Will this person help me grow my business with their expertise?".

Not Having a Proper Bookkeeping Process
This is a must have for EVERY business. Most businesses don't even think about this until it's the end of the year, and now it's "tax time". Did you keep any records? Are they even organized? You'll want to hire a bookkeeper in order to keep all your receipts, statements, invetory, invoices, payments, and income organized. Most bookkeepers are really busy at the end of the year, through April, getting other businesses up-to-date. They may not be able to take on new clients during this time. Plus, not keeping up-to-date records as you go, will make more of a mess to clean up for the Bookkeeper at the end of the year, and end up costing you more money.