Contractual provisions allowing for termination upon breach take many forms. Some termination clauses allow a party to terminate upon the basis of any breach; others only allow termination in the case of a material or fundamental breach of contract; yet others supplement rights to terminate upon material breach with rights to terminate in the case of persistent, non-material breaches.
Because of this variation, a contract should be closely studied before a notice of termination is dispatched. As well as looking at the termination provisions, you should consider the contractual notices provisions (if there are any). To whom should contractual notices be sent? By which means: courier, mail, email, fax, or some other form of delivery? When will notice be deemed to be given?
If you are terminating for breach, you should of course be confident that the other party is in fact in breach of contract, and that that breach does give rise to a termination right. If you are in any way unsure of your position in relation to termination, take expert legal advice.
In addition to looking at rights of termination and methods of giving notice, you should consider what obligations might arise as a result of termination. Typically, these post-termination obligations are covered at the end of the termination clause, or in a special "effects of termination" clause, but they can appear anywhere in a contract.
In any case, this template letter of termination is designed to be used in these circumstances. To use the template, you will need to add some situation-specific information, including details of the contract, the clause under which you are terminating, the breach and the consequences of termination.