I am only a hobby seller, but have learnt a few things.

Cost permitting, always send via trackable means.

I don't sell to Italy, Turkey, Sth America and India anymore as too many items are stolen in transit.

Maybe start by selling on ebay.com, America is a big market and good to learn from. Just factor in a $9 customs fee on top of postage if items are over 453 grams or express post.

Only accept PayPal.

Clearly describe items with pictures as some don't understand english well.

Other than that, start small as you have been doing and good communication is the key to a happy buyer.

🙂