How to encourage buyer to rate our model

The most effective way is to make crappy models - unhappy customer will always leave you a rating. ;]
Most of the happy customers are too busy to make their projects and rarely find time and motivation to go back and rate the model.
It's unfortunate, but it's how humans work.
Those who do, are the best customers you will ever have.

I think that if they go to download the model again after they have purchased & dowloaded already then they should be prevented from doing so, until they leave a star rating maybe via a pop-up window? A bit like when you fill out a form and have to check a "i accept terms & conditions box". It's one more click for the buyer, but means a lot more to the seller.

When I rarely have received a review it have been after I have done some model support. There have been some problem with texture, missing file or likewise and then I have fixed the issue fast. So my limited experience with reviews underline Trimiteks point.
On the other hand, maybe it is the correspondence that do the job. It transform the models from just some file bought on internet to a model created by a human. It becomes personal. Just a thought I got while writing this.

There are people who leave rating without asking and there are people who doesn't rate, even if asked. At some point, i was explicitly asking everyone who tried to negotiate price through price offer, to leave positive rating in return. While everyone would agree to that condition, only a few persons actually left a rating, so eventually i stopped asking for that.

AFAIK, cgtrader is politely reminding to the customers to leave ratings, but if someone doesn't want to, there's no way to force it. Overall, the tendency is not to leave rating - my first 100 sales went without single rating...

Wouldn't worry to much about it, very few people give rating and probably very few actually read them and make decisions based on them (unless they are negative).

Don’t know if a rating actually has any value besides feeling like a nice compliment?
I’m convinced if tomorrow my ratings/reviews would disappear I would not lose a single sale for it.

Single most important thing to get right is producing something that has value for someone ells and properly put it on display and provide detailed info about what they are getting, if done right then all rest will follow (sales, position, ratings, likes, etc.)

@Mantas, I've just sold a couple of models and for the first time I have sent them a PM to say thank you and offered myself available for any assistance or information they require (and also a cheeky happy new year :D) - Only time will tell if this approach works. Also...I hope they like what they got lol or I might be kicking myself in the ****

I have only sold four times in the site and I got one review, but I think my low model/sales count is not big enough to draw any conclusions from.

Sold quite a lot of models on here but only have 1 review and that wasn't even for a model lol. No idea if it really matters or not to be honest.