Only the top five cryptocurrencies have a decent trading volume for you to consider start trading. The other ones might give you some profit, but if you are willing to trade large amounts, it's not worth it, because of the low liquidity.
if you have bigger balance in your account then top five crypto currencies will have a good chance to help you to make profit but if you only small until medium balance, then i will suggest you to pick from the top twenty or even top fifty because there is much coins that could help you to make big profit. we don't take about short term buy and sell but we buy and hold for a while until the price is increase significant then we can selling to earn big profit. but if you want to use short term strategy to buy and sell, then you need to pick a coins which have a fast moving for buy and sell.