Should I include the keywords most relevant to projects in the title? For example, if I am looking for an anime artist, should I also include related words in the title? For example: manga
I want to know more about how the Upwork search engine works so I can get more people to bid on my projects. Does it help to include a keyword more than once?
Make sure your payment method is verified, then add the job under the proper category with relevant tags (freelancers select the categories they feel most competent at, and are being presented with recommendations from those fields).
If you've done that and still not getting proposals, the budget might be too low for what you're asking. The budget could even be too high if you have little hiring history or if it's the first job you're posting. Maybe you can break it up into smaller jobs with lower budgets just to build a history and lower the risk possibly perceived by the freelancer.
I don't think Upwork is going to tell you exactly how the search algorithm works. But here's what I've been able to work out, as a freelancer and with a little experimentation.
1. Some freelancers might just list all the jobs in their job category without entering any search words. Be sure to select all relevant categories in case a freelancer filters by category.
2. If they do enter search words, those words are normally searched for in the job post's title, description AND skills.
3. It's possible to search for words in the title only, but I doubt that many freelancers do that. I wouldn't worry about the title as far as the search itself is concerned, but of course you want to have an effective title that will be meaningful to freelancers when they see the list of search results.
4. It's possible to search for skills selected from the skills list, rather than entering arbitrary search words. I doubt that many freelancers rely on this alone, but you might as well select relevant skills in your job post.
5. I don't think the number of times a word appears is relevant, though I can't swear to that.
6. Freelancers can apply additional filters for things like budget range (on fixed price jobs), location, verified payment method, etc.
The best freelancers (very different from top-rated or having all sorts of badges) find worthwhile work without you needing to do a whole lot. A job description of what you want will draw good freelancers if the money's right. Be sure to specify what you want accomplished rather than a way to get there. If you've developed the perfect solution I'm going to skip you, because you've likely developed the perfect solution to the wrong problem. Really good freelancers need to be able to sort out with you the result you're seeking, then use whatever they need to in order to deliver it.
My filters are set at expert, $251, less than ten applications, less than 30 hours/week. I prefer validated payment, but it's not a deal killer. If you've invited a laundry list of people it's clear you don't know what you're doing. Issue invitations using a sniper rifle, not a cannon.