i joined the gym a few weeks ago and ive manged to put on 6lbs of muscle in just under 3 weeks. I have a training programme and do all the exercises every time i go, which is all weekdays, my programme is:

5 minute bike warm up - level 2
24 minute bike programme - level 1 - 8
5 minute row or 5 minute run
chest press
lat pulldown
easy pull up machine
dual overhead press
bicep curl
stomach crunches on the ball
jack knives
 takes about 1 hour 30 minutes

so far i havent taken any supplements, would you advise me too? Ive taken creatine in the past, but it didnt suit me to well! im 16 and weigh 10 stone 6, I found it relatively easy to see changes when i started weights, before i was a slightly tubby but very active male. Now im seeing a leaner self, i feel a lot happier about myself and becoming slightly obsessed with the gym! Just goes to show what having so much time off after my gcses does!

All good stuff mate but mix it up and dos some different exercises as well/instead because:
1) this will get boring
2) your body will get used to it and improvements will slow
3) you are not targeting all of your muscle groups