Sandman, the nutes you use for VEGGING should be high in N (the first number... say, 10-5-5 or 15-10-10) and the nutes you use for FLOWERING should be high in P, the second number. As long as the numbers are higher than the rest then you should be fine, and always start off on a quarter strength of what it says on the packet. Only start using nutes after 4 weeks too, that way all the nutes in the soil will have been used up.
If you cant get your hands on any nutes, then a good source of them is from soil. Just grab a healthy handful of soil, whack it in a pair of CLEAN tights and then sit that in 4 gallons of water. Leave it somewhere at 16c for a week, and voila - water with nutrients in! Always try it out on one plant first though incase you nute burn it or you havent used enough soil. With a bit of practice youll get it right, but those measurements have always worked for me and my lows