In a perfect place the good posts that author put a lot of effort would be rewarded the highest and other less. This stage here is hard to achieve though. Many people pop for a short while and miss a lot of them. Curation projects have their limits and rules they have to stick to. Some stick to the people they know and don't look for anyone new. Some have rich friends. Some like long posts with a lot of info, others short FB like. There is no simple criteria I guess. Someone will like it and vote it, other wont.
The only good advise I could give is find a way to enjoy posting and sharing your stuff. The more you compare yourself to others the more frustrating it will be.