It's not easy from the beginning without any reviews to land your first client on freelance websites like upwork. It's not just how perfect your proposals are, clients want to see recommendations from others that you're good to work with.
one way to deal with it, is to offer free samples of your services, mention that in your bid proposal. if it's content writing for example, you tell the client you'll provide the first 3 articles free.
Also you should always mention that you're ready and available to start working on the project right away, and make sure to stay online. finally you should notice when there are less people placing bids, so that you'll be available to submit your own bids. I've used this trick in the past on freelancer.com, during the day, for Indian time zone, you'll find 100's of bids within hours, most of them with better reviews. so like around 12AM upward on Indian time zone, i am available and almost every night i'll get a response from one or 2 clients since not many people are bidding. i believe upwork is filled with Indians too, so you need to find the time they're not active, even if you're Indian yourself, you have to be active through the night to keep bidding.
Start with low paying job listings, just for the sake of earning your first few reviews, most of these projects with low pay, don't attract much bids, so bid on such projects, there is a high chance of winning such bids especially if you can provide work samples.