if I think personally a safe way to invest in cryptocurrency is :
1. the project runs according to the roadmap and whitepaper that has been made;
2. cryptocurrency that we invest in already has a product;
3. the team always updates about the progress that is happening in the project that we invest;
4. invest in project that are in the top 1-500 in coinmarketpcap (have a high volume);
5. the project we want to invest has been running for a long time (if I personally never invested in a new project), because investing in new project has a greater risk than we invest in old project.
Safely invest with cryptocurrency choose altcoin have potential on higher price and have position on the top coinmarket cap, you choose coin above twenty rank on coinmarket cap, never invest with altcoin have rank under two hundred on coinmarket cap because too risk for your self and your investment assets with lower price, keep investing with top altcoin like bch, eth, xrp and neo coins.