need some tips for flowering bag seeed..

Sup, my plant on to the right the biggest one is going into its third week of flowering soon.. and i was wondering should it be bigger or have more white hairs as this stage it has some at the moment but not coming directly from the flowers yet. and also i have a plant i started from 12/12 which has gotten pretty big its only about a month old or so how do i switch it into flowering by simply giving it flowering nutes?

http://tinypic.com/r/16kwc39/6

On the surface I can warn you that due to the UNKNOWN genetics it will be hard to say what size the plant should approx. be or at which speed growth will occur. Moreso, attempting to cultivate a plant to its full genetic potential is gonna be a ruff ride as long as it resides inside of a coffee can. I would say transplant to another pot, but that looks to be EXTREMELY tricky considering the lip on the can. However, your other plant that is in the red cup should be safe to transplant into a bigger pot. I would recommend at least a 2.5 gallon pot.
I can pretty much conclude that your plant that is in the coffee can is either ROOTBOUND or is soon to be.
Also, what Kelvin temp bulbs are use using. In flowering you are going to want to use something like a 2700K bulb.
Lastly, I would recommend that you do some research and learn as much as you can about cultivation. We all make mistakes, but its learning from them is what makes a difference. Most of cultivation from my exp. has been a matter of trials and tribulations. Good Luck and I hope I was able to help. FIRE IN DA HOLE!