Don't feel discouraged. Remember that every start/beginning is the toughest. Once you break the ice it gets a bit easier and you will only go up.
I was pretty lucky getting my first UpWork client. I also faced a similar problem as you - I was a complete newb on the site versus all of these highly experienced freelancers with amazing reviews. I honestly thought that I had no chance whatsoever. I was primarly focusing around writing, developing and the sales and marketing category.
Then one day, out of nowhere, I actually got hired for translation. One of the clients urgently needed somebody to translate a text in a language that isn't really widely popular and that I happen to know because I live next to the country. You could say I was blessed in a way. So, we ended up working together, not only for that one task but he also rehired me after on 4 different occasions. This gave me a nice little boost that I needed and the good reviews. He recommended me to his friends and so it began.
What I am trying to say is - it can happen completely randomly and sooner than you know it, you will have a nice side income.
Meanwhile, I do agree with Cchaen. You can always try to lower your rate/wage. Also, which categories are you trying out? some categories are harder to get work in - it depends how much demand and supply there is. Consider picking categories that don't have too many people crawling around