there is at least a dozen of dialect in england , i assume you want the london one . bbc would be a good choice , but somehow i think that is not really london one , just standard one . maybe better find a native speaker and copy from him

When you say "British accent", I guess you mean the clean RP accent used by well-spoken and educated British. Naturally, listening to songs and watching movies/TV shows will make you familiar with the accent(s). Your best option is to voice chat with British people and listen to how they normally speak. If they're patient, ask them to listen to your efforts. :)

Эталоном Английского произношения считаються дикторы ВВС. Поэтому, лучший вариант копировать их... Там же можно и поучиться: http://www.bbc.co.uk/worldservice/learningenglish/

BBC radio is very good. Also old British films

Thank you that you are not advise me to kill myself then I also wouldn't have any problem with a British accent :)))