First understand the following points -
1.MarketCap
2.What does the coin do?
3.Sentiment attached to the Coin? - Yes the sentiments play a very major role in favour or support of the coin.
4.On which exchange the coin is listed? - Yes there is a very major role of exchanges in pumping the price of coin.
5.Read about the coins from a very good source, just google you will find lot of good sources for reading about the coins you want to invest in, see the maximum price it has reached.
6.Most smaller coins are paired with BTC/ETH or stable coins, i.e coins whose value will always remain 1$, therefore BTC/ETH will always pump as soon as money is flowing into the market.
7.Never press any buy button in the flow of emotions.
8.Sell with smaller profits, you will gain some confidence that ways.
9. Always play safe, first invest only which you can afford to lose, second try to put stop loss, so that if the price goes way too much low you will at least not lose all your funds.
10.Keep your funds safe, try to keep them in your wallet, if you are planning to store them for longer run, then hardware wallet is preferred, else a paper wallet is also safe.
Now coming to what coins you should buy?
You can read about 200+ coins here -
https://coinswitch.co/coins Read the future of the cryptocurrencies, there team, there technical and fundamental analysis etc.
My advice to you - Buy some BTC and ETH, but do your own research before taking my advice.