How to attract more buyer on CGTrader?

Make better product.

Do the best you can with your models. After that I don't think there are many things to do. It's up to the clients

CGt gets already millions of visitors per month and bucket loads of buyers, (https://www.similarweb.com/website/cgtrader.com#overview).

Some sellers just don’t get them and then believe they are not there.
Solution sounds simple but its indeed noting more then make something they want.

Looking at your offers I can tell you the soccer ball can be made faster then one can purchase it. Same for the pushpins. The clock has lots of competition looking better. Probably the school bus and farm house have most chances having its distinctive look. The other architectural models and fire arms, don't expect sales on those.

There are thousands of these models so if you keep making that type of models its going to be very hard time selling.

This is my honest opinion, I can be wrong about it but don't think so.
Best advice I can give you is train like hell and create distinctive items.

Your models look good and I like some of what you have there. I agree with what has been said so far, but I would like to add that it seems most of your models have only basic textures and some do not have any at all. That's fine for some things if you are offering native materials on UVunwrapped models, but models that come with well painted PBR texture maps would typically sell much better than those which do not. Unless you are selling 3d printable models, most buyers are looking for "plug and play" solutions for games, vfx or arch-viz and will be more likely to purchase a model that is complete with non-overlapping UVs and good PBR texture maps. Even if they have to pay a little bit more for it.

Character models

I don't think you have to "attract" buyers, I think it's all about supply and demand just like anything else you want to sell. As iterateCGI says, you have models that are already flooded in the market place and sadly yours don't stand out from the crowd. That doesn't mean they're bad, it just means that the buyer can see 100s of the same models and therefore buying yours would be just down to pure luck. If you don't specialise in a particular area and just want to model whatever, whenever then it is a good idea to employ the analytics to figure out what you should be making.

If you check the most searched for items and the most sold and the number of models available and do a bit of maths you will soon learn that making those items isn't your best idea. Making a helmet for instance when there are already 10,000 of them for sale really lowers your chances of a sale in that area. If you don't have a particular target audience then make models that stand out in a low saturated area.

Good luck in the future and happy winter solstice.