By Rieva Lesonsky

When you’re a startup business owner, there’s something new to learn every day. (Most days, there are about 17 new things to learn.) That means no matter how great you think your business idea is, you’re going to need to fine-tune it as you go.

Lots of entrepreneurs get freaked out by this idea. They think they have to “get it right” from the beginning. This couldn’t be more wrong. Even if you wrote a letter-perfect business plan, you’ve got to be flexible enough to make changes to it as you go.

When I launched my company a little over a year ago, we had a great business plan in place. Then the Great Recession came along, and since then almost nothing has happened the way we had planned. It’s been a rollercoaster ride, but one that taught me a lot of lessons. Here are 4 of the most important:

1. Get a Plan B. And a Plan C. You may even want a Plan D.

2. Get help. The federal government offers tons, for free. Visit your local SBA office, or start with the SBA Web site (www.sba.gov) for information. Business.gov is another great resource. SCORE (www.score.org) or your local Small Business Development Center are fantastic places to get one-on-one advice.

3. Get social. Using Twitter has been one of the best things I’ve done as a business owner. I’ve connected with tons of contacts old and new, including potential partners and clients. (Follow me at @rieva).

4. Get friends. I don’t know how any business owner does this without support. Having a few people you know you can turn to when the going gets tough can make the difference between success and failure.