One of the most important things is trying to learn how to negotiate without using your heart. Use your head - try to reason and make sure you see your neighbour's issues and problems with the situation. Some people might be more amicable if they realise you're not out to mislead them.
Planning authorities and local councils may be able to connect you with a Boundary Adviser, who can learn your circumstance, act as a mediator and also give expert planning advice as to how to resolve the dispute. They're often people with a number of years experience in the industry, and can guide you through any legal processes involved. In addition, you may want to get in touch with the British Institute of Chartered Surveyors, who have a specific boundary demarcation team.
Understanding how your property boundaries are marked out is vital. If you have a dispute, it is essential to know your facts and gain a documentary of evidence. Take photos and mark out how the dispute has occurred. Once you know the facts, it'll give you a better chance of sorting out any problems with professionalism and reasoning rather than hot-headedness.
A lot of disputes which occur are often not as serious as first seemed. It's important to find out whether the boundary violation is simply a mistake...sometimes, just being calm, considerate and understanding helps to resolve a lot of issues.
If you require any more advice regarding boundary disputes or property law in general, contact a specialist planning solicitors such as Brighton solicitors Burt Brill and Cardens who can aid you in your disputes.