Selling gold online often shows the best prices, but it parts you from your gold before any price agreement: you post your items, the valuation comes later. It is the riskiest route for the seller.
You request a prepaid envelope, send your jewellery, the dealer appraises it and makes an offer. If you decline, your items are (in principle) returned.
For most sellers, a local shop offers a better price/safety balance: valuation in front of you, immediate payment, direct recourse. Compare your city’s buyers first.