Unless your doing some punky power chord things always try to use alternate picking.
Youl want to avoid the DOWN DOWN DOWN DOWN DOWN DOWN DOWN thing if you do that, I did when I first started. Its alright to do when your doing certain rhythm things but its a bad habit, and it ****s your wrist up :/
Try to learn the Minor Pentatonic scale, Major/minor, harmonic minor, those are pretty common scales.
"the" major and minor scale are the same, its just a matter of where your start out on the fret board, Modal crap which isn't something you need to know when your first starting, but its nice to learn later.
Find some good lead guitarists to listen to. Van Halen, Stevie Ray Vaughn, whatever your musical preferences may be and listen to what they do. Try to pick up on their phrasing and try to imitate it when your messing around with scales.
Theres no magic way to be a good lead player, it helps to learn some licks from songs you like to get you going though. To get good at it you just have to play and play, jam with friends, or try to play over backing tracks. I have a weird ear thing though so I have a problem playing with songs or to backing tracks.
Dont put your fingers too close to the metal frets when your playing, youl just deaden the note. Press firmly in the middle of the fret board.
When your practicing always try to have a goal at the end of practice. Like learn a certain part of a song, or learning a new scale position.
I dont know how your picking/hand strength stuff is. But what helped me alot was just playing every note on the fret board linearly, squeezing as hard as possible with my fretting hand and picking as hard and steady as possible with my picking hand. Play as fast as you can comfortably and slowly push it from there.
Play until it hurts, if your hand doesnt start to hurt your not getting stronger.
Did you go to a music school or take formal music theory classes pertaining to an instrument, because if you didn't theres tons and tons of ridiculous music there to be learned.