Know what you need Create a list of must-haves for your building as well as a wish-list for things you'd like to have but could live without. Calculate how many square feet you need and determine any special needs, such as plumbing requirements, windows or air conditioning.

I recommend:  Use OfficeFinder.com's office space calculator to determine how much space you'll require.

Find buildings Several Web sites offer national and local search tools for commercial buildings. Many of these services allow you to search by type of building — retail, office, industrial.

I recommend:  With more than 380,000 commercial properties listed for sale or lease, LoopNet.com is the place to turn for commercial real estate. Simply complete a free registration form to become a member and search for properties nationwide. For a modest monthly fee, CoStar Commercial MLS lets you search for office, retail, industrial and more. Cushman & Wakefield also offers an online commercial property search. BizSpace also has listings in 16 markets.

Hire a pro Commercial real estate transactions can be very complex. Your best option is to solicit the services of a real estate professional who specializes in commercial properties.

I recommend:  Most national realty firms, such as ReMax and Prudential, have commercial agents. Coldwell Banker has a special division that offers tools and resources geared to small businesses seeking a commercial building. You can also find a broker in your area by searching Cityfeet's Commercial Broker Directory.

Financing your building Consider getting a pre-approved loan so you'll know exactly how big your budget is. Approach your current business banker first to determine their commercial mortgage loan rates and terms. When you already have a relationship with the bank, you may be able to negotiate more favorable terms.

I recommend:  Fill in an online application at C-Loans.com, which will send you a list of the commercial mortgage lenders with the lowest rates for your loan. At BuyerZone.com, you can receive commercial mortgage loan quotes from major providers.

Get an environmental report If your building, or the surrounding area, has been contaminated by any hazardous materials, you could be required by law to perform very expensive environmental cleanup. Ask the seller for a disclosure statement that reports any known or possible hazards. Obtain at least a Phase I Environmental Site Assessment for any building you're considering.

I recommend:  AssessCo.com and ESA1.com conduct Phase I Environmental Site Assessments nationwide.

Check zoning laws Investigate your local zoning laws to make sure your intended use for the building is allowed. If it isn't, you can try to change the zoning laws or obtain a variance.

I recommend:  Find state, county, municipal and local land use and zoning law sites at MegaLaw.com.

Seal the deal with a contract Any real estate deal should be spelled out in detail in a written contract.

I recommend:  Find sample commercial real estate contracts at BuyIncomeProperties.com.

Get title insurance If you buy a commercial property and a lien shows up later or you discover that someone else had rights to the property, it can lead to financial havoc. Title insurance guarantees that you hold all the legal rights to the building and will allow you to recover any losses you face from such liens.

I recommend:  TitleInsurance.com lets you obtain quotes from up to five title insurance companies.