you have to be the judge on buying and selling, since ihave been here i have heard if you lose 3% sell, if you gain of 5% to 8% sell, but you really have to go by how you feel, i keep one stock JRCC and i usually buy it around $30-35 and i have made well over 8% profit.
this contest ends Sept. 1st and then they are going to handle the prize format differently, there is another post here in this forum explaining it see New Contest and Prizing Format.
as far as points go you just make posts and you recieve 200 points for each post 50 points for each trade. as of right now the do not have the store up and running but eventually your points can be redemed for things.
hope i helped have fun and good luck