Thanks
no matter what you hear learn how to use google
in 90% of the times with a quick search you can always find enough information about things you encounter that helps you make up your mind about whether or not they are scam. for example if you google the name of a cloudmining service or the term cloudmining in general with the term "scam" you surely will find topics about it which you can read like this https://bitcointalksearch.org/topic/cloudmining-101-ponzi-risk-assessment-878387
and if you didn't find you can ask about them on forums.
always keep in mind that when something looks too good to be true, it surely is not.