Try to get lead the mob, rather than follow it. Learn who people buy. Some players are bought during the week, no matter when they're playing. The downside of this is that most of these players are expensive, and if you're just starting may not be able to afford these players, but there are still bargains out there. Learn to read the herd.
Some stocks move a large amount simply because everyone thinks the stock is worth buying.
Others fall because people think the stock will lose money. You want to try and figure out what will lead people to buy or sell a certain stock. Big trades and big game losses are two of these things. Look for bargain players. Not all bonus players are bought.