Well, I wouldn’t say expert, but maybe experienced 
lol
Honestly, your item can sell itself if you actively provide your buyers support and be responsive.
Participate in discussions. Word of mouth is probably the best form of marketing in my opinion.
We periodically have campaigns on Google, Bing, Facebook and Twitter. Bing seems the most successful.
We get a lot of referrals through Google, but we see more sales in a month when marketing on Bing.
Facebook can be a costly marketing tool but it’s always been a really successful one for us.
Reviews - writing reviews about your item and sharing it with websites that promote them through referral.
You basically provide the website a review of your theme, details, and they link it with their own referral link.
We’ve done this on a few websites - though I cannot honestly say we’ve had a lot of success in that.
BuySellAds can be expensive, but we’ve also seen a lot of success in it.
There’s a lot of ways to market your items. Not sure if we’re the most success in that approach, but it has helped. We don’t regularly run campaigns. Sometimes we do it every 2-3 weeks, other times we’ll do it bimonthly. This usually helps in the budget department when you find your spending more on marketing than your profiting (that can happen quick so be forewarned).
Honestly though, I go back to word of mouth as I’ve always found it to be the best.
Hope it gives some insight. All the best in your marketing and good luck with future sales!
