#1
What is the best way to practice? Short, but frequent sessions or guitar marathons?
What is a good way to build up speed? I want to play metal and I want to shred (which I know will take a lot of time). I just want to make sure that I get the most out of my practice time.
#2
It kind of depends on what fits your regular schedule. If you've got a job or something it'd be hard to get in lots of solid practice time, other than the weekends. I wouldn't suggest "marathons", as you call them, but keep the practice sessions fairly long; as long as you can, actually. Anywhere from 2-4 hours; even more, if that would work for you.
ESPECIALLY...
...if you want to shred. Shredding (though it frequently gets ridiculed) is one of the toughest and most advanced guitar methods. It's not something you should shoot for right away. After all, nobody new to driving goes and signs up for the road test right way, know what I mean? Start slow, perhaps some easier but still metal stuff, like Black Sabbath, Metallica, etc. Once you can handle stuff like that, then work your way up to the faster stuff. Don't expect to start by practicing shred and instantly being good at it, because you have to start much smaller and slower.
But once you get enough practice time in, it'll eventually become easier. Just remember to try to keep the practice sessions long, but not so long that they're strenuous and your fingers bleed. Trust me, it happens.
#3
Yeah, I do have a job as a cashier at Albertsons.I'm art time though. I knew that shredding was going to take a lot of time and patience. I really want to be a kick ass guitarist.
#4
Quote by jackson001
Yeah, I do have a job as a cashier at Albertsons.I'm art time though. I knew that shredding was going to take a lot of time and patience. I really want to be a kick ass guitarist.

Being able to shred isn't hardly enough to make you a "kick ass guitarist", though. You'll have to devote about 80% or more of your practice time to learning theory, practicing your scales, memorizing your modes and patterns... any "shredder" will tell you that it's not the ability to play fast that makes you good. Trust me; it's better to be a medium-speed guitarist with a vast knowledge of theory than a clueless shredder who can blaze through Eruption in 30 seconds.
Not that being a shredder can't be rewarding, but just make sure you spend a LOT of time working on scales and stuff. For starters, I'd suggest getting the red Guitar Grimoire book; the one with scales and modes. It's like the Oxford Dictionary for guitar; well worth your money.
But other than that, good luck with your practice!