On average, one confirmation will take about an 10 minutes, however some sellers might require many confirmations before they consider the money sent. This is done to prevent double spending and other similar issues.
If several hours have passed without your Bitcoin transaction being confirmed, just wait. If more than 72 hours have gone by without confirmation, use one of the following two methods:
Use the Replace by Fee (RBF Protocol)
Use the higher fee Double-Spend transaction
Replace by Fee (RBF Protocol)
Please note that not many wallets support the RBF Protocol. If you are not able to mark your transaction as "replaceable" when sending, your wallet doesn't support the RBF Protocol. If you are unable to use RBF, you still may be able to cancel the Bitcoin transaction by double spending with a higher fee.
Simply make a new transaction equal to the amount of the original one and send it to yourself. Make sure the transaction fee on this is significantly higher than the original one you paid. If you don't follow this essential step the method is not going to work. You may need to use another wallet or specialized software that allows double spending for the transaction to be broadcast to the network.
If everything goes well, miners will pick up the new transaction and your Bitcoin will be back in your wallet. Most miners and wallets have safeguards against double spending, that means that this method might now work.
Not many know there are ways to speed up bitcoin transactions. The so-called "Bitcoin accelerators" allow you to pay a fee and speed up an existing Bitcoin transaction. There are many scammers and fake websites, Sellix.io doesn't endorse any of these services.
The only way to ensure a transaction is going to be confirmed in a timely manner is to pay the recommended transaction fees.