Trading is when you buy a altcoin for a low price and sell it when its price comes up so you will have to keep an eye on the market.
Risks? The most common risk is the altcoins short life span, If you search in google, you will see that most altcoins got dumped in just a short period of time.
The other one is failing to predict the price, example is when a certain altcoins price is getting lower and lower so you sell it all to avoid losing money more, Sometimes the coins price might increase again.
the price increase after being dumped very far only for popular coins such as ethereum and the rest. most likely to be dead and deleted from the market after there's none activities around . would prefer cut lose rather than really losing the whole of money on just an altcoin