Cover advice: Look at the most popular/trending covers for your genre. What are elements that they share? If you look at BL, as an easy example, most covers will show two male figures interacting in some way. If you can identify those trends, then I suggest, from a marketing standpoint, that you incorporate them. Those are signals that readers look for when they are searching out new titles.
General advice: the best advice I've gotten so far is to post EVERY. DAY. If you can post every day and have a quality product, that helps you stand out in the algorithm, and you will have a better chance of appearing in 'Popular' and 'Trending.' I got this advice from Bijou Paradise - she's been #1 in Popular for about two weeks now with her novel Human, and is still going strong. I've been on the platform for 2 1/2 weeks, and I'm in Popular and Trending very consistently doing this.
Now, if you can't post quality work every day, then settle for consistency. If you post every other day, or every three days or every week: don't skip a post, play with the time of day until you find one that you feel works for you and then stick with it, and make sure each chapter has something engaging happening, big or small.
Last, do take the extra time to make sure you are putting out work that looks professional. Edit, revise, edit, revise. Posting every day helps a lot - but people won't keep reading if they get turned off by something that's hard to digest.