1.   Not forming a LLC or corporation first.  You should go into negotiations with your separate entity already formed and ready to be named as the lessee.  This one step may dramatically limit your personal liability on the lease.  If you can avoid a personal guarantee, you’ll sleep easier at night.

2.   Not knowing what to ask for from the landlord.  Do you want to abate the rent until you open for business?  Do you need financial help with the construction costs?  You need to think through what you will need before you sign the lease, because it will be too late afterwards.

3.   Not understanding the terms.  What is a triple net lease?  What services will the landlord provide and which services are you responsible to provide?  If you haven’t negotiated a lot of leases, the terms can be confusing.  Make sure you understand all of them before signing anything.

4.   Falling in love with one location.  There is a lot of commercial space out there and you should be willing to move on to the next opportunity if you can’t agree on terms that make sense to your business.  Often, an entrepreneur will make changes to his or her business model to fit the lease – a backward dynamic.  If you believe there is only one perfect location for your new business, then I would seriously consider a new business.

5.   Not understanding the costs of build out and start up before signing the lease.  Facing construction sticker-shock after you signed a long-term lease is a terrible way to start off in your new location.  Make sure you have a firm handle on the projected costs of having your proposed location prepared open BEFORE you sign a lease.  Once you’re in, you’re in and the landlord is not going to be sympathetic when you can’t make the rent payment because you under-estimated the start-up costs.

Keep in mind that in most commercial lease situations, the landlord and its agent will have much more experience than you.  They do this type of work everyday while most entrepreneurs will only negotiate a handful of leases in their working lives.  This makes it crucially important to have experienced help in the form of a real estate agent and/or lawyer on your side to make sure you get the best deal possible.