Studying & Working Visa's

I am planning on applying for a working and or travelling Visa for the UK and Canada, and possibly some Asian countries down the track. I was wondering if anyone had some advice on this. Anything and everything would be appreciated. Past experiences, advice on where too go, where too stay, who to contact, to work or to study? I haven't really researched much at all as of yet, but getting some hands on advice from fellow travelers would be invaluable. I am thinking of contacting one of those business's (forgive me, I can't remember the name of them) that basically arrange your entire trip for you and help you find work over there, what are your opinion on this? Yay? Nay? Amateur mistake? I'd like something concrete and secure. Would anyone favour studying over working abroad? Is it dependent on what you plan on studying or what you have already studied? I'm almost completely lost and starting from square one, so any advice anyone could pass down would be amazing! Thankyou in advance!