Hello!
where do you trade your cryptocurrencies? do you have any tips for a beginner on how to start?
Just build experience, that's the best tip. Since while you are continously progressing your trading journey, you will soon automatically adopt new ideas on how to deal with the current price volatility of your chosen alts.
There are also lots of cryptocurrencies to trade so you can't avoid using multiple trading platforms at the same time. Sometimes you want to used, for let's say Bittrex, but your coins are not present. All trading platforms are applicable for beginners, what you must need to understand first is their interface so that you can navigate on their features easily.