Hitchhiking / Hitch Hiking in the UK tips & Faqs?

Hello
Im planning to do a hitchhike for charity in may from Bristol to Cumbria (M5/M6) So not a bad route , i play darts to the West of England and we are playing Cumbria so thought i would combine the two.
Is there any tips i should know or any tried and tested means or is this a good route as they go.
Another question to ask which may be stupid but in past experience how long have you waited for a lift?
i know thats a silly question but someone may be able to shed some light on it who has done lots of hitching in the past.