Be careful to read any restrictions that have been put on the land there are some plots here in Scotland that can't be fenced off due to habitation concerns of wild animals. It is not just nature reserves that come under the banner of protected habitat. 1 way that I have seen people get started is to look for uncared for or derelict land that is part of an existing farm and approach the land owner directly. Some areas are not suitable for large scale agriculture so it is left unmanaged.
Just some ideas hope it helps.