Never reuse an address
A wallet can create a practically unlimited number of addresses from one seed. Giving a fresh address for every payment received costs nothing and stops anyone from linking all your payments by looking at a single address. Reuse also exposes the public key once you spend, which is a small extra risk in the long run.
Coin control
Your wallet holds several UTXOs, each with its own history. Coin control lets you choose which ones a transaction spends instead of letting the wallet pick. Spending two UTXOs together tells the world they are both yours.
- Label each UTXO when you receive it: where it came from, who knows about it.
- Avoid merging coins from an identity verified exchange with coins received privately.
- Consolidate small UTXOs when fees are low, and only coins that already share a history.