I have been fortunate to learn 5 basis weight lift to increase ones strength. Along with proper nutrition and cardiovascular training your strength will increase.     

First of all when lifting weight always have a "spotter" (someone to assist you in training).

When I was in college, I was fortunate to learn these techniques and this style of training from Olympic athletes and Champions. I have personally taught this to high school athletes who went on to play in the NFL, as well as many looking to increase their strenght.

 There are 5 lifts you need to know, they require free weights. The front squat, the back squat, the clean and jerk, the snatch, and the bench press. You can find them in any weight training book, or any trainer should know them. Once you identify these lifts, stressing technique not poundage, find your maximum weight you can lift. Always warm up before you lift, starting from neck to ankles.

 After indentifying your maximum weight on each lift, do 6 sets of 6 at 70% max. resting about a minute in between sets. If your max for the bench was 200 then your sets would be 6 sets of 6 at 140 lbs. Do this 3 times a week, lifting monday, wednesday and friday, not lifting on tuesday and thursday.  Checking your max every 8 weeks, and increasing your rep weight if needed. On your nonlifting days you should do cardiovascular exercises. as well as stretching exercises . After lifting is complete cool down with a light jog.             

 These exercises are to increase your strength. If you desire to be a bodybuilder then you should use lifts that isolate muscle groups. Always make sure to eat plenty of protien and drink plenty of water