I am using both platforms. Fiverr and Upwork are somewhat similar but way more different when you get into getting clients. For a beginner fiverr is recommended.
Here is an screenshot of one year old fiverr account.
Am i the best at these niches? Nooooo
Am i really good at delivering the projects? Nooooo
Am i using any secret hidden system? Nooooo
Am i the best Seller? Of course
Is it a Top Rated/ Premium Account? Noooo
Then how am i capable of doing it? Because i make my clients believe me. It's all about how you present and how you talk to clients. Lot of sellers (Especially in India- No offence) talk to clients Sir/ Madam, I call them by their name or username. Yes client is always right. Most sellers do not know their value. I do and i over sell. My gigs are starting from $500+ when most top rated sellers charge $125 and others $5-75. I do not proceed with clients who are worried about budget. Do not delay the delivery. If you do then they will see ton of issues and you will get into an endless revision cycle.
For Upwork i am sending proposals customized to each client. There are lot of bots automatically sending proposals to clients. Sometimes they get lucky but most of the times they fail. Prior to an agreement i ask ton of questions and then send them the final proposal to start working.
How much money i make? Doesn't matter
How much can you make? It is depending entirely on you.
My suggestion to any newbie or an active seller on upwork/ fiverr - Spend much time learning the platform before selling. You will learn a ton. I am also still learning.
p.s. - I swear to god ,while writing this i just checked a new upwork profile created and approved this week. I just sent 5 proposals. Guess what??
I might be stupid to say this. I do believe in Karma.
Cheers.