Yeah, some good advice above. I am a sea, lake and river fisherman, myself.
One thing I would add is that it is always a good idea to go and watch some other fishermen, see what they do, what fish they catch, what gear they're using, etc.
If you find that you maybe want to ask a fisherman a couple of questions or something, always start by telling him that you're a fisherman too, or in your case that you're just starting out, then, in my experience, they instantly drop their gaurd and start to talk to you as if you've been mates for years. Imo, fishermen are among the most approachable and friendly people I have ever met.
There are loads of dedicated fishing forums about, loads of books, even video's to help you along the way. Ask questions in tackle shops if they aren't too busy at the time, things like good spots, what you expect to catch there, what gear to use, etc. One other thing I'd recommend you don't do is go out and buy loads of expensive gear straight away. A lot of fishing can be done really cheaply, for example simple Mackerel fishing - which is one of my favourites - just requires a basic rod and reel set which can be had for less than £10, together with some feathers or something - I could stand and do that all day! I have never been to Cornwall but I have heard that there are some great little Mackerel beaches there. Also, lures, spinners, floats etc catch fishermen just as much as they catch fish, so don't go mad and buy a load of gear without knowing exactly how to use it and whether it's actually worth the money.
One other thing, be careful, especially if you're clambering over rocks or whatever. Try to always go with a mate if you can, or where other people can see you, especially when you're just starting out, as fishing can be quite dangerous sometimes, even to experienced guys.
It can be quite frustrating at times and very rewarding at other times, just take it steady, try to think about what you're doing all the time, if you're not catching any fish, change something. Get yourself a good fishing book, learn to recognise the fish, learn how to handle certain fish as some of them can leave you with nasty cuts if you don't handle them correctly.
That's about all I can think of atm, there's a few fishermen on here which I'm sure will offer any advice and help you along your way. Good luck, have fun, and remember, they call it 'fishing' not 'catching'.
