Many have given all the necessary advice but here is another thing you should put in mind.
Altcoins are difficult to trade because of high volatility they possess for long period of time, it's always difficult to hold supports and resistances unlike the Bitcoin and other high level coin on market cap.
Though, you can choose to scalp them especially when they are fundamentally bullish, it's so profitable to easily roll in and out of the market but be cautious of that as well.
Avoid shitcoins, they get pump hard but the reverse will send you bad image of trading, you wouldn't want to try them. Gold luck.