Just like any "investments"...
1) Dont pile in at any given moment... Scale in.
2) Buy on the dips... A good thing to remember (just like stocks) is when you are getting scared of the price drop and considering selling, its probably time to buy.
3) Buy from reputable places. I bought mine from NWTM and APMEX.
4) Be careful of the advice you get from people. There's a thread from last year where ppl were discussing the huge rise in silver. PPL were "piling in" thinking the end was near... Well, those ppl are now sitting on a loss. I have a friend of the family that owns silver at $50oz.. FROM 1980 Hunt Bros cornering. They are still a loser as well.