I'm still new to this. I'm looking for some tips on determining legit and fraud. In other words, how can I tell a good investment from a scam.
The websites that simply promise to double your bitcoins after a period of time = scam, period. Then, we are ICOs where you could invest into t, you must look to the team (the developers and If they are able to deliver that project), escrow, and such details, usually, If you check those as should be, you should know If the project is something serious or another shitcoin scam.
Finally, we have exchanges and gambling sites. You can't really tell for sure since sometimes they start legit and turn into a scam. The only advice I can give here is to not store your bitcoins in their sites for long term, just trade or whatever and withdraw instantly.