Upwork is a great site. I recently was introduced to it this past summer. At first I didn't know what type of gig I was looking for. However I was a CPA with about 6 years experience in Public and knew QBO and some apps that went along with it (T-Sheets, Aero, etc.).
The thing with Upwork is you really have to be honest and seem personable when you make a proposal. Make it short and brief and personalize it to the position. No cookie cutter proposals. I learned this the hard way. I finally landed on a gig that actually turned into something large. I now have a little side hustle that is bringing in about the equivalent of 1/3rd to ½ my Public Accounting salary. The work is never steady and often some weeks require 20+ hours of side work and some require only 2. But that’s showbiz.
Like OP, all I have is a good internet connection, laptop and some free time. But don’t get discouraged. There are tons of jobs on Upwork and each one in the bookkeeping/accounting/taxes arena get upwards of 50+ proposals so you need to stand out. Try to specialize in something, like you are an expert in nonprofits or financial cap tables or renewable energy start ups. Also try not to undersell your time. There are many on the site that will bid $10 per hour to do a job that should really cost $50 per hour, just to get the job. Stay at the rate you are comfortable with and explain in your proposal – that you are aware other people will under bid you but they won’t be able to deliver the same quality of work. I have gotten some jobs even though I was the highest bidder.
Another thing, make sure to say that you are a native English speaker from the USA. Upwork is a website accessible by anyone with internet so you get a lot of people from India and China trying to win jobs. However most employers like fluent English speakers so that is always a good thing to mention.
Obviously you need the knowledge and experience to consult and help businesses remotely. That is a given.
Hope all the info helps. I am a pretty big advocate of Upwork because you can actually land good gig’s on it and get real money. One more thing, once you actually get in the position of interviewing you will have to then decide if you want to take your business off the website or work through the website. Working through the website requires Upwork to take a fee out of the total you will be getting paid. So you can either ask the employer if you can work off the site (to avoid the fee), or try to price the fee into your proposal.