Freelancers, what are some tips to identify a good client by looking at the gig?

The title says it all. There are just 24 hours in a day and only a small chunk out of this can a freelancer take out for finding new jobs. Besides, there are tons of sites like Upwork, Freelancer, golance, fiverr, etc. so its just not possible to go into detail of each and every posting. So, just while you are skimming through a job posting, on what criteria do you decide that here is a wonderful and genuine client whom I'll enjoy working with?