For brand new authors, you can’t only rely on having a good product, since not everyone will know that it’s good right away (no reviews, ratings, sales, etc.), so your best bet is to not only make a great product, but also some great marketing, make sure your profile is appealing and professional, and try to make your product previews stick out from everyone else. Your item will appear on the front page of whatever marketplace you submit to (once it’s approved), but only for a short while, depending on when it’s accepted, it can be there anywhere from a few minutes to a few days, so make sure that your item thumbnail is interesting and stands out, because it will be mixed in with many others, which most people just glance over, so make it eye catching. The best items are the ones that can be heavily customizable, giving the customer lots of control on making it fit to what they want, so try not to make them too restrictive if you can.
Also, be prepared to have many rejections. New authors seem to have stricter requirements, so even if you think your item is amazing, it can still most likely be improved, so don’t take a rejection as them saying your item isn’t good, take it as an opportunity to make it better. When I first started, I had my first 10 to 15 items rejected at least once before finally being accepted, some had many rejections, and some were never accepted at all, but I definitely feel like that forced me to improve a ton.
Overall, just don’t expect to become a success overnight, definitely push for that, but don’t expect it. It takes time and work, and even then you may find that this is just a good place to make a little bit of pocket change rather than making a living, we have plenty of both in the community, but the majority seem to be the former, like myself.
I hope it all goes well for you, and if you ever do have issues with an item getting rejected, or have other questions, you will usually be able to get some useful answers and feedback in the forums here, so good luck!