Look at the graphs for one or two minutes to get a feeling what is currently a low and a highprice for the companys. (first 3 recommended at the beginning)
Afterwards (I did so) buy as much as you can,wait until the price is higher than the buying price, wait until it decrease again or buy another product.
In a few hours you can make or 200K with 1K start money.
But keep in mind that the low and high prices are not fixed. Sometime it falls beneathwhat you expexted as low. You have been warned. ;)
PS: try to invest all your money before the end of the current month (TAXES!) :)