My strategy to avoid the divers when you purchase is to only buy a stock when it's already below it's 50 and 200 day moving averages. The farther below those, the better, if it's a good company. Then you aren't falling from a high back down to it's average, which I see happen a lot. Try to get into the stock when it's already low, if it goes down, you get an extra discount, if it goes up, profit city.
I also try to avoid volatile industries like banking, airlines, cell phones, etc and stick to tried and true name monopolies like Coke, Pepsi, Harley Davidson, Wal-Mart, Costco, McDonalds, etc....companies that won't go out of business so I can hold onto them for the long haul if I get in too early or whatever.
While AIM may not always be the best strategy with every stock (Apple going from $20 to $200 to $120 for example), it will save your ass and it will create structure for your trading, which is the #1 problem I see. I don't have to think of when to sell or buy, I KNOW when to sell or buy and until those triggers are hit, I can safely ignore my investments. I look only when the markets are closed and usually only trade every other Friday night or so. Makes it simple, which is the key in my book.
Invest in peace...