it's never too late mate. as long as u buy in at a right time and exit at the right time, any coin can be a good investment.

Try to keep a diversified portfolio.

Also have a clear idea of how to divide up your capital, and then invest accordingly (e.g. 40% for established coins BTC/ETH,etc  ; 40% for promising alts ; 20% for short term flips/pump and dumps/high risk stuff)

That usually helps to keep your portfolio steady. Might not be the best and maximizing profit, but at least you'll always have some level of fallback and wont be too prone to losing everything at once.

One thing people often neglect is the importance of having a stop-loss.

When u set your order, you should be mentally prepared to close out the order if your losses exceed a certain point.

Most people tend to panic and hold on to their coins in an obvious downtrend, hoping that price would go up.

Sometimes it pays off and price rebounds, but sometimes it can be disastrous if price never returns to prior levels (e.g bancor).

Trading is a lot about discipline and it helps to stay rational.