1. Ask for a rent free period. Depending on the demand for particular property and its condition, it is always worth trying to negotiate a rent free period with the landlord.
2. Give careful consideration about who is taking the commercial lease. The ideal scenario is that you take the lease in a separate limited company as oppose to you own personal name as a lease can expose you to significant personal liability. Landlords may not agree to this they may require some other security if the company has little or no financial history.
3. Ask for a break clause. (a right to terminate the lease early). This will give you flexibility in that you might commit to say a 6 year commercial lease you could perhaps bring the lease to an end on each anniversary of the term by giving the landlord and agreed period of notice.