Let me add to some of piltogg's suggestions
6. Like he said, don't lift everyday; I'd recommend only 3 lifting sessions per week...other days can be cardio / light cardio with stretching
7. Each of the days you lift weights in a given week should target a different muscle group. E.g. Monday - chest+arms / Wed - shoulders+back / Fri - legs+somethin...this lets muscles rest, repair, and grow
8. Protein, protein, protein, in the 1 hour after you work out, and then the next morning (whey powder is a good investment)
9. workout for at least 45 min keeping your heart-rate near 140 (when possible) - 8-10 should be your target rep counts per weight exercise...more if you are doing pushups, pullups, or other non-weight exercise.
10. after a while, switch up what day you workout what muscles to avoid boredom and confuse your muscles
11. Good luck