Disable change addresses. They are the worst when it comes to reveal your bitcoin addresses. Then, always, when you want to do a transaction, think about from which address to send. If you don't want that an address is revealed, maybe because you are invested in a scam company with it, then send the funds to an exchange. Every transaction to that exchange let you give a new address there. You don't want them all go the same address. Then you can send them back and you have fresh coins.
If you sent already from one of your addresses then think about that too. Maybe you don't want that one of the receivers of the transactions does know that you sent to the other service and so on.
Simply use your brain and decide which amount to send from which address.
But everytime you put money in an exchange the transaction is linked to some data of you, at least an IP and email address. Also, for the mixers you are trusting that they don't keep logs.. its centralized. Hopefully in the future there are better alternatives. It works for now tho and generally should give you a good level of anonymity if you want that.