I'm a 22-year-old who made nearly $100K in revenue on Depop last year. Here's how I did it and my secret tips to sell successfully.

• Theresa Sobocinski is a 22-year-old product designer who made nearly $100K a year on Depop.
• She sources her items from thrift stores, SSENSE, and other popular girl brands.

When I was a teenager, I wasn't really given an allowance, and I felt bad asking for money. My family is middle-class, regular people. So I tried to find other ways to make money.

I was pretty into fashion in high school, so I started selling clothes on Poshmark. But I soon realized that Poshmark takes a lot in fees: there's a 20% fee on sales over $15.

So I moved over to Depop. Depop charges a total fee of around 14% on each transaction. This includes a 10% commission on the sale price, plus a 3.3% transaction fee, and an additional $0.45 charge for each item sold.

I grew my account organically to around 7,000 followers. I did this by posting high-quality try-on photos with consistent backgrounds, using relevant hashtags, and regularly refreshing my posts on my feed.

I source my items from thrift stores, SSENSE, and other popular girl brands

For used clothing, I like to source from thrift stores — Goodwill near me has really good inventory. For example, last fall when leather jackets were really in, Goodwill was selling them for $20 and I was able to sell them for $80. I made a $50 profit off that, so the net profit there was pretty high.

For other clothes, I also go to SSENSE, an upscale online department store with large sales up to 70% off every twice a year. It's crucial to keep an eye on trends and what's in demand. But be cautious of return policies, especially final sales. I prefer to avoid those because I'd rather repair unsold items than hold excess inventory.

I also source some items from popular girl brands like Realization Par, Mirror Palais, and other department stores that carry these brands. You have to catch the sales because these items are usually expensive — I tried to buy tops with ribbons on sale from these stores because they were trending this season.

I recently went to Europe this summer and saw that everyone was wearing Silver Onitsuka Tiger Mexico 66s — they are very sought-after shoes in Europe. I thought that trend would carry over to the States, and when I came back home a couple of weeks later, I started seeing the shoes on my TikTok feed. So I bought a few of those and was able to sell a pair for a 200% markup.

Now I'm on track to make $100,000 in revenue this year

I usually ship items out two days a week and dedicate about an hour or two to printing labels, packing everything up, and sending them to the post office the next morning.

I check my Depop messages every morning and during lunch to see if anyone's interested in anything. At the end of the day, I'll top off the labels and bundle all the packages together — this takes about an hour in total.

I store all my inventory in my garage and try to keep things organized: shoes in one section, arranged by size, and clothing in another, with cardigans and sweaters grouped together.

I don't have a label printer, so I print six labels on one page using my computer and cut them out. If it gets overwhelming, I'll ask my mom to help with the cutting and taping.

To make shipping easier, I sometimes schedule USPS pickups so I don't have to carry all the boxes to the post office. I usually send out 12-15 package items 3 times a week.

Before starting Depop, you need to define your goals

There are two ways to selling items: you want to get rid of some clothes or items you no longer need, and you want to make some extra cash.

The other kind is more hardcore reselling — you'll have to source items on the internet, usually stuff that's on sale and have the potential to become popular.

For example, this season, Adidas Samba shoes are really in and very hard to get, and the popular sizes for women are seven to eight. So you have to find items that are trendy, more scarce, and price them higher.

Essential tips to succeed as a Depop seller

1. Always "refresh" your items and use hashtags

This is something that's not intuitive — and Depop didn't make it super clear for sellers either. You need to constantly go to your item page, click "edit" and "save changes" to get it back on the feed.

So, if I post an Adidas item today, for example, it'll show up at the top of the feed based on when I posted it. But after a few hours, other people will start posting Adidas items, so my listing will go down and get buried. In that situation, you'll need to refresh to get it back up on the feed.

In addition to that, you need to use hashtags. You can place up to five hashtags to increase the visibility of how much your item is shown. Typically, I'll try to fill all five hashtags to fit into some category.

2. Model the items with something that looks good

When people can see what it looks like on you, they can imagine how it might look like on them.

If I'm selling a top, I'll usually pair it with a nice skirt or whatever looks good with the top. It sells better this way than if you just placed it on your bed and took a picture.

3. Friendliness is key

I will try to respond back to customers as fast as I can. If I have a break, I'll go through messages and respond to people and try to give measurements to people. Being a nice person goes a long way.

When people come back to my store and purchase a second time around, I get happy.

4. You'll need some money to get started

To really get started, you'll need to have some money to outsource your items because there's a huge difference between a casual Depop seller and someone that's trying to actually do it for a bigger net profit. I think having anywhere between $3,000 to $5,000 would be good to kick off your business.

But you don't really need experience selling on other platforms to start a Depop. It's a process and you'll learn as you go — you'll see what's popular, what's working versus what's not.

If you've successfully created a secondary or passive income stream and want to share your story, email Aria Yang at ayang@insider.com.