The metronome is your freind. Start slow and gradually speed up at your own pace. There is no set time period for gaining speed. We all learn both mentally and physically (your hands) at diferent speeds.
You have to find what works for you and run with it. ==========================
What I said above is from what I learned from doing things the hard way. A good example is practicing 12 hrs a day doing the wrong things the wrong way. Trying to force speed just makes you sloppy, and if you're like me and seriously self critical.... its not going to make you want to practice anymore. THATS BAD.
The mechanics and repetition are what builds speed. If you arent doing it right from the start.....youll be working 3 times harder later on to fix it.
Find a patient teacher and work with him or her. Thats alot better than learning from tabs and trying to figure things out like timing on your own with no guidence.
Wish ya luck my freind....awesome instrument to learn. Got me 3 kids hahah. I shouldve been a bass player
Make sure you're comfortable, no matter what you're working on. Everyone is built differently and there is no one way to do anything correctly. Just make sure you're clean, and don't get ahead of yourself. Also keep in mind that while speed is awesome, it's not everything. If you can't play a certain lick as fast as you'd like, set aside 15 minutes a practice session and play it as perfectly as you can to a metronome. Then, as silly as it may seem, work on something else (improvising, learn some theory; if you're doing alternate picking, try some sweeps or legato) then come back to it in a little while. You will find that you are better at that lick than you were when you started, and you've learned a whole bunch of other shit to boot. Always remember that a well rounded musician who isn't as fast is infinitely easier to listen to than someone who can only sweep pick fast or alternate pick. And don't forget about rhythm guitar!!! The metronome is your friend but you should also know when to turn it off and make music. Find some other musicians who are interested in similar playing and jam with them, trade licks, riffs, write songs or whatever. When I started working on chops a couple of years ago I surrounded myself with other awesome players. You'll learn much faster with others than on your own. other than that make sure you're enjoying it. I've gone on month long metronome marathons before, and while yes, these to help your chops, they make playing guitar, and your guitar playing kind of boring as hell.