This web site can hopefully give you some advice and direction on how to make the successful sale of, purchase or investment in commercial real estate.  Most of the information in this site, such as listings, statistics, document forms, etc., are self explanatory.  

 Some pitfalls and opportunities to look out for (and which are dealt with in this web site) include the following:

Opportunities

Cash Flow - If there is one feature about real estate that appeals to us it is the cash flow from the property.  Real estate investments generally sell with cash income that are in excess of those available on stocks and bonds.  For example the ICREIM/IPD index (covering mostly larger real estate properties), shows that the total return for office properties (income and change in value) was 265% between 1987-2002, despite the fact that office buildings are still well below the 1988 price levels, for the properties covered by that index.
Tax Shelter - Real Estate provides two important tax benefits.  The first is that any gain in the price of the property is treated as a capital gain and only one-half of the gain is included in income.  For example if a property is sold for a $ 100,000 profit, only $ 50,000 is included in your income for tax purposes.  A second important tax benefit is the right to depreciate the building on a property.  For example, if a property is purchased for $ 1,000,000 and one-half of the price is allocable to the building on the property, a tax deduction is available of 2% of the amount allocated to the building in the first year and 4% yearly on the balance thereafter (eventually, when the property is sold the money sheltered by the depreciation is repaid unless there has been a decline in the value of the property attributable to the building's deprectiation).  How much of the sale price is attributable to the value of the building on a property can contribute significantly to your after tax cash flow.
Risk/Price Volatility - Studies have shown that real estate shows high returns with what may be a better balance of risk and return than stocks and bonds offer.  By risk, we mean deviations from your expected return. One important factor (but not the only factor) contributing to the lower risk is the fact that income is often locked in by leases that have several years to run, makes it more likely that your actual returns will match your expected returns.  A diversified portfolio which includes multiple tenants helps reduce the risk associated with unexpected developments (repairs, economic changes, vacancies etc.).  It is because real estate tends to be so low in risk that investors are often tempted to take on the risk associated with mortgage financing.  That option offers both the advantage of dramatically increasing the rate of return but also the risk associated with financing.
Inflation Hedge - The Market Data section includes data on the Construction Price Index.  Essentially it shows how the cost of construction of new real estate buildings has grown over time.   The are numerous factors that affect real estate prices and it would be wrong to say that all real estate will grow in value at the same rate as inflation.  Property prices can increase by more than the rate of inflation (as for example with multi-unit residential properties) or drop in value altogether (as appears to have been the case with the office building sector).  However, studies show that there is a significant correlation between inflation and property values and that some of the change in price in property over time, can be explained by the impact of inflation.   Some of the effects of inflation can be seen by referring to the Construction Price Index.  For example, between 1988 and 2002 construction costs for new buildings have generally grown by about 40%.  
Increasing Value - Astute investors will look at ways of increasing the value of a property.  This may involve "sweat equity", improving the quality of tenants, and/or updating the property.  A high efficiency furnace, for example, can substantially reduce heating costs.  Similarly, a carefully review of the property taxes may show that the property is overtaxed and even if it takes several years to implement a reduction doing so can add significantly to its value.

Pitfalls  (the top four traps to lookout for)

Property Taxes - understanding property taxes is crucial to avoiding serious errors.  For example it is not unusual to find properties being marketed for sale with uses or characteristics which have not been correctly incorporated into the property tax assessment - a potential tax problem for a new owner down the road if/when the error is corrected.

As an example, properties with more than 6 residential rental units are taxed at a much higher rate than buildings with less than 6 residential units.  Yet we have seen cases were properties contain more than six units but are taxed as being comprised of six or less units.  In such a case the correct taxes could be close to three times as high as the actual taxes.  In another case we saw a property retroactively reassessed for a period of three years resulting in a tax bill of $ 70,000 additional taxes for the previous three years.

Insurance - There was a time that you could call your broker ask for an insurance quote and have several competitive quotes in one or two days.  No longer.  It can take months to get an insurance quote and in some cases you may find insurance companies refusing to insure your property.  Premiums are growing dramatically and have been known to double.  It in looking at existing insurance costs, you need to consider if there is likely to be an increase in insurance, whether you can get new insurance, and whether the seller of the property even has the correct insurance coverage.
Cash Flow/mortgage financing - strong reliable cash flow is one of the best features of real estate.  It can however lead buyers to serious errors particularly in the low interest environment we have today.  Low interest rates and high mortgages can lead to enormous rates of return on property.  With high financing, however, borrowers face the risk of increases in interest rates, as well as increased vulnerability to unexpected expenses or reduced income.  But even if the rental income/expenses do not change, the owner will find themselves in a complex tax situation down the road.    The tax shelter from depreciation drops over time leading to increased income taxes over time.  Even more serious are the mortgage payments.  Initially mortgage payments are mostly interest (and therefore tax deductible).  Over time a large part of the mortgage payment repays principal and is taxed as income.  As a result the owner is paying taxes not just on the income it received but on the income used to pay down the mortgage.  Thus the cash flow over time shrinks dramatically, unless the mortgage amortization is rescheduled.
Due Diligence- Most investors have heard the term "Buyer Beware".  Unfortunately, in commerical real estate the best one can usually hope for from a Vendor is that they say little and leave it to the purchaser to investigate the property.  Unfortunately, sellers too often engage in varying degrees of exaggeration or deception.  Buyers must rely on compentent advice from their professional advisers.

Ultimately, there is no substitute for experience.  The astute investor learns to rely on his/her own experience as well as that of experienced professionals - such as lawyers, accountants and knowledgeable real estate agents.