Here's how you do it if you're Evil Valve:

The DENNIS system of Hat Sales

First: Display value.

Display highly rated workshop entries to people as they start the game.

Next, Engage individually:

Tailor suggestions, give players their own feed: utilize the data you've collected from each player's account. (it isn't stalking, it's metadata!) If they've played a lot of Drow Ranger, show that highly rated drow ranger immortal. If they always vote for sets with particles, show them some sets with particles. Find the right match.

Now it's time to Nurture that interest:

If they click through and visit the workshop and positively rate the item, show them that immortal on their feed more frequently! Leave the item there on their feed for a couple of weeks, still, don't leave it on the burner, let it simmer! mix it up and show loading screens etc often enough that the player keeps checking at that space for something new when they go to launch the game. Your item will go from an exciting but fleeting idea to a familiar friend. Baby it. Nurture that Interest!

Don't forget the most important step: Neglect the customer.

It's important to make them wait, because waiting is the hardest part!

Hide the item from their feed - they might forget about it, that's fine. Many will feel remorse because it seems like the item they loved somehow didn't make it into the game. ("I didn't mean to get my hopes up, but it had a 5 star rating!") Let them know you're a corporation and you have the final say in what goes into the game. While before they merely wanted to buy the item, they should, having lost it, be convinced that they actually needed to buy the item, (but alas, it's gone) Neglect that Customer!

Now OP, NOW you want to Inspire hope

Hint at the contents of your next update. Hide some bits in with the latest round of tickets. Let reddit work it out. Make them whisper about it. Maybe that item isn't gone, after all. Who can say? This step is the most critically timed. If you wait too long the players will overcome their irrational hope without you. Wouldn't want to lose all the hype over something you've put in the game files already, it would have to sit there for years unadded. So Inspire Hope with care!

Okay, you've tantalized them enough and it's almost time to update the game with new items.

Finally, Stabilize Emotionally

There is no way to live up to their expectations. You are a game developer, you know this innately. What you can do is catch them at the nadir of their free fall. You got their hopes so far up that they'd need a mattress to land on. They'll trip over anything you put in their way, other items become hurdles between themselves and happiness, remove those hurdles for a fee. This is when you release the chest promising to end the rollercoaster ride and Stabilize them Emotionally!