If it is on the ETH address in your ERC20 supported wallet then you can trade it over the exchanger by sending the tokens.

For example, if you have IOST token and you want to use them to exchange for the purpose of getting BTC, ETH or any other coin that you need then just go and find the exchanger where it is listed first. In case of IOST it is already listed over 4-5 exchangers and lets pick Binance. Second step woudl be create the account on binance, then search for the IOST token in the wallet. There you can see the deposit option, by selecting that you can get the deposit address for the IOST. (You can send only IOST on this and however same procedure follows for other tokens too). Then come to your main wallet where you holding the tokens. Here copy the address of exchanger and paste it in the field of "To address". Input the amount and generate the transaction and click send. After sufficient confirmation you will see the IOST transferred to your exchanger wallet.

From here on wards you can trade your token with all the available pairs and thus obtain other currencies. If you get them converted to BTC then you can use BTC further to convert into fiat on your local wallet and then get the fiat money into you bank account.