You have highlighted something important regarding freelance sites. Most of the clients read the workers' reviews, and this is very valuable when it comes to being hired. If there are people willing to write reviews on your behalf, it would really help.The foremost freelancing site is upwork and fiverr. I have tried both but I have not being hired by any of the two freelancing sites. Most especially if you do not have reviews on the site . If you want your gigg to be ranked high , go get people to write positive reviews on your account.