what is a day trader

Hi all so called daytraders.I am new to this game and would like to know what is exactly the objective of a daytrader.Is it to trade daily and make a small or large amount or to buy a stock and hopefully will sell within days for a profit.Is this how one can make a living?.And then how much money one can place on a stock safely,if there is such a thing.How do you find the winners.What are some of the best sources of information,in order to aquire knowledge.Is there some rules or guidelines for safe daytrading. Currently I am holding some blue chips and a couple of small stocks.
Your replies will be appreciated