Always try to do your own research, even if you see some good opinions on specific coin in the forums like this one.

I think a good idea is to start with the basics, try to learn as much as you can about crypto world in general before investing: https://youtube.com/playlist?list=PLQ794-ev8UM73wdWAtX6H588QJnuuV6yq

Take your time, do your research and create your strategy before investing money into it. If you're thinking about safe long-term, coins, with high market cap like Bitcoin and Ethereum seems to be the most reliable options.