First of all, I would like to welcome you on this great platform of opportunities, learnings and creative ideas. It's really good to know more about the Upwork policies, strategies and tips because millennials often make some common mistakes when starting as a freelancer that may lead them to face certain unforeseen setbacks, even I had some
You are doing a good job thus far and I can see that you have successfully completed 3 jobs in June itself. If you will move with the same speed and passion, soon you will be awarded with the Rising Talent credit. Some of the things that I saw missing are the graphics in the portfolio. You may add the Graphics to your profile (a screenshot of your writeup, an image of the media outlet where it gets published etc.) and tests. The tests add value to your profile. So, its good to take the test as much as you can.
Apart from this, I would recommend you to take up freelance assignments in areas that you are good at and it is always good to know your worth. Quote your client a price which justifies your level of expertise and skills. However, it is recommended to do some market research and learn what your contemporaries are charging for a fair competition. That's just a suggestion
All the best!