As a newbie, I have little experience in choosing a promising altcoin and there must be some important thing that I don't know now in the process of choosing a altcoin. I want to stand on the shoulders of giants and I hope you can teach me something. Thank you.
You can check for the top coins in CoinMarketCap. This will give you a clear idea as to what coin/s you can consider purchasing. But note that prices in this site is quite higher due to the averaging it does from different exchanges.