1. Match your name on eBay to your IG handle and other social media.
This will make it easier for them to find you off platform which saves you on fees that eat your margin and helps people trust you're real
2. Feedback.
No one will trust your $2,000 dollar watch listing if you've never bought and sold something on eBay.
Sell some things you have lying around to get feedback.
Buy and sell some items, preferably related to luxuries but something is better than nothing. Cologne, shoes, wallets, jewelry accessories and watch accessories.
3. Raise your selling limit.
Some of you won't be able to list your watches right away because it's price is higher than your limit.
Call eBay and tell them you want to increase your selling limit so you can sell some high end watches. If they say no, call again and ask a different rep eventually you'll get it.
Also, look into getting your account verified by supplying extra info but this might be for business accounts only.
4. Apply for PayPal credit before you need it.
PayPal will give you a credit line that has no interest on payments for the first 6 months.
Have this in place in case you ever need to protect yourself in a deal by paying with credit instead of cash, you can buy anything else on or off eBay with PayPal credit too.
5. Optimize your photos.
Very simply take photos using the "square" sizing (AKA 1:1 ratio or 1600x1600 pixels) on your phone or camera so that your photos are easier to see and eBay's zoom function works best. Preferably a JPEG file.