A lean economy means many of your competitors have been knocked out of the ring. That's good news and bad, says Kevin Daum, a New York-based marketing consultant and author of the book, Roar! Get Heard in The Sales and Marketing Jungle. "The good news is that you no longer have 30 competitors in your space. You now have four or five," he says. "But the bad news is those four or five are actually doing it right."

This means your marketing strategies need to reflect your best efforts. But, Daum says, entrepreneurs often miss the mark when it comes to everything from advertising to hiring consultants, because they don't have a clear marketing strategy. Here are three of the most common mistakes to watch out for:

Mistake No. 1: You don't know the return on your marketing investment.
Too many business owners throw money at marketing without taking the time to figure out what they're getting for those dollars spent, says Daum. If you can't tie the expense to a specific result, you may be wasting your money.

Take Helaine Smith, a Boston-based cosmetic dentist. She spent $1,300 a month on a double-page phone book ad for eight years without measuring how much business it brought in. She stopped running the ad only when she had to cut costs to move into a pricier office space. It wasn't until Smith revamped her website in 2005 and again in 2009 that she got a clear sense of how online marketing can help her business. She added a wealth of content and optimized the site to put her at the top of keyword searches.

Related: What You Don't Know About SEO 

At the same time, Smith began tracking how each of her patients heard about her practice, specifically through the Internet. Now she knows that the $36,000 a year she spends on marketing through her website and blog brings in about $70,000 a year in new patients, a figure that helps justify the expense.

Mistake No. 2: You rely too heavily on your sales team.
When sales are slow, business owners have a tendency to put more pressure on their sales staff, trying to get them to sell more in order to ramp up revenue.

But making your sales team the company's sole savior can lead to a slippery slope in business, according to Daum. While a sales team is part of the equation, Daum says the real work should come from marketing.

"Sales people usually go out and say what they want to say," Daum cautions. "The job of marketing is to make that sales process efficient."

Make sure that the materials your sales staff are using when talking to customers are clear and consistent. The sales pitch, company brochures, website, and any other marketing tool should all carry the same brand message.

"In this [recessionary] environment it needs to be all about the customer," Daum says.

Related: Five Signs You Need a Marketing Makeover

Mistake No. 3: Your website reads more like an ad than a helpful resource.
If your website showcases only product features and pricing, you're missing a huge opportunity to connect with potential customers, says David Meerman Scott, a Lexington, Mass.-based marketing strategist and author of the book Real-Time Marketing & PR.

"The biggest problem that small businesses do again and again is focus way too much on their company. . . and not enough on the problems and needs of the people they are trying to reach," Scott says.

For Sean Harper, 30, co-founder of Fee Fighters, a comparison-shopping website for credit-card processing, getting beyond the product and making the dry field of credit-card processing sexy for customers was no small task. After renaming the company from Transparent Financial Services to Fee Fighters last year to be more appealing to customers, Harper and his five-person staff also added useful content to the website such as weekly videos, a free e-book, a $25 incentive referral card for existing customers, and an active Twitter stream on the topic of credit-card processing.

In Smith's case, providing potential clients with information about dental procedures online is a huge part of her website. She maintains an education page with links to articles, e-books, and videos on topics from dental implants to bad breath and dental tourism. Smith even has a "community resource" tab that links to local businesses like a pet shop and Thai restaurant in her neighborhood.

"Everything has to be in line to show what kind of person you are and what your business is like," she says. "The patients love [the website] and it's part of my brand. It shows right away that I'm different and I'm really good."