For me personaly, one of the main indicators is managers' feedback. Of course you should first go deeper into details & pay close attention to the reviews.
Haven't got profit more than 10$. Consider airdrop is not very profitable. Otherwise I just haven't got that much luck. Cause to my mind it's kind of lottery.
Putin shows interest in cryptocurrency. The Kremlin website published Putin's instruction on the results of the meeting on cryptocurrencies on October 10. The President instructed the government and the Central Bank to submit amendments for the regulation of ICO, cryptocurrencies and the registration of miners. So maybe it may somehow affect the price of bitcoin.
If you take a look at a chart of bitcoin prices, you'll see that it shows a clear dominant uptrend for most of the year. To my mind, you can tell that bitcoin value is going up and should be invested in. Of course there are risks of failing. But what business doesn't have them?!..
You should do regular backups of a bitcoin wallet. Also always use the latest version of bitcoin software. And of course your password should be at least 16 characters long.