It's not difficult get a British accent. There are a lot of things that you can do. You might like to start off by watching a movies (with characters speaking in British accents.) Harry Potter, Peter Pan, ect. Then after you throughly understand what "British accents" are, you can practice by reading a book aloud in a British accent.
P.S. You may watch Shakspear of you like, but that won't help much. Because nobody talks like "I shall have thou ice-cream." anymore these days.