Hi Vanesa,
Congrats on that first closed project! The first one is usually the hardest, so you already did an awesome job by landing it and getting good feedback. 
As a freelancer, it is definitely very important to learn to sell yourself as a specialist. I've seen people charging x10 times the average price for their services just because they are good at sales. I'm not a genius sales-woman either, but since May 2019 I did get hired for all but one jobs that I was interviewed for (besides the ones I rejected myself), so here's what I can think of from my experience:
1. After I get to the interview stage, I try to talk less about myself and more about the project. Ask for the details, suggest what and how we could do, try to "connect" with the client by giving them the feeling that we're on the same page and have the same vision for the project. Basically, just get them to talk as much as possible about the project. I can send some portfolio examples or answer questions about my skills if the client asks, but I don't initiate this kind of conversation myself. If I'm at the interview stage, they probably have already seen my profile and assume that I do have the skills to do it, so I don't bother talking about it anymore. For me, there are 2 very simple reasons behind this strategy:
• While other freelancers might be still discussing their qualifications or budgets/deadlines with the client, I already know everything about the project. Now if I already know everything and the client thinks I understand the job and can do it, why would they even waste time telling other freelancers all about it? At that point, it just makes it easier for them to hire me than tell the others everything that they've already discussed with me. The budget/deadlines conversation follows, of course, but at that point it's up to me to agree/refuse, because they already want to work with me.
• This strategy allows me personally to get to know everything about the project fast and to see if it's actually something I can do well. I don't want to waste my time either
2. That one job that I didn't get after passing to the interview stage - I didn't get it because I was too late with my reply and the client has already hired someone else. In fact, on Upwork, sometimes, time is everything. You might be the absolute best expert for the job, but someone else replied a couple of hours earlier, and the job went to them. This works in sales in general I'd say, all the amazing sales-people that I know reply to inquiries immediately, within minutes. I'm not saying that you need to wake up in the middle of the night to reply, of course, lol but just try to be as fast as you can. I don't allow myself to have "antisocial" moments anymore, if there is a message - I go and talk.
3. As a new freelancer on Upwork, it is important for you to have some competitive advantages over other freelancers. Imagine someone as skilled and experienced as you are, but also with 20+ completed projects and good feedbacks on Upwork. What can you do to get a competitive advantage over them, if the client is choosing between you two? Maybe offer a lower price at the beginning, or a shorter timeline for the project. Or think of something else, give the client a reason to hire you instead of a professional with the same skillset but also more Upwork experience.
4. Try to analyze your conversations with the clients and see if there is a pattern on when exactly they disappear / go with someone else. If you find out there is, it will be easier for you to understand what you can change in order to land those jobs.
• If it's after they see the examples of your works, maybe next time you can try to include the examples that are more similar to what that exact project is about. Or on the contrary, send examples with more diversity. Try different ways and find out what works best.
• If it's after you discuss the budget, maybe try to lower your prices until your profile gets stronger.
• If it's after the deadline discussion - again, see if it's possible to give shorter timelines and work faster at the beginning.
You get the idea 🙂
Remember, it is the hardest at the start. This is when you need to put in the biggest effort. After your profile gets stronger, you can set your own rules. But for now, you are a beginner on Upwork, even if outside of it you're an amazing professional and expert. You need to create social proof for the potential clients here on the platform, that is work history and feedbacks. You already did the first step by landing&completing that first job with good feedback. I'm sure it will all work out great for you, because judging from your portfolio and the key achievements in branding, you are indeed an amazing expert.
I hope that some of the insights from my experience will be helpful for you. Sorry for such a long text 
And good luck!
