How to Improve Privacy
Privacy is not absolute. Privacy depends always on your adversary. If you want to hide your transactions from curious users like your neighbours, it is sufficient to use different addresses for each transaction. Many advanced wallets offer this by default.
If your curious adversary has more resources it might be possible for him to track the network, see usage patterns, get KYC (Know your customer) data from crypto exchanges and online shops, be able to break into your computer, or even put pressure on you personally. In such cases using different addresses adds no privacy.
An effective tool to cover your tracks is mixing services. They try to break the link between two addresses by sending them through many transactions and mixing them with other user’s funds. But they are a chapter for themselves.