a. Use Multisig Wallets: Of course you know that in multisig wallets, multiple private keys are needed to sign transactions before the coin can be used or spent. This will help prevent prevent a single compromise or coercion from draining all your bitcoin asset.
You need a strong password for your wallet, and add an extra passphrase for it. The passphrase needs to be backed up separately with your wallet mnemonic seed and it plays like an extra security, somewhat like a co-signer as if anyone only gets your wallet mnemonic seed, it's useless as to access that exact wallet, a passphrase is mandatory.
c. Diversify Brands of Hardware Wallets: Some coins can be stored in Trevor while the remainder can be stored in Ledger Nano x as the case maybe. This way, bug or an exploit in one type will not compromise everything.
Trezor is good, but why Ledger?
There are better hardware wallets than Ledger.
[LIST] Open Source Hardware Wallets.2. Physical/Personal Security: As we all know, robbery is always associated with physical assault, so here are some suggestions that may reduce the possibility of such occurrence.
Physical attacks can cost you a life, not only your bitcoin or cryptocurrencies so stay humble, anonymous with bad people and avoid phyiscal attacks as best as possible.
https://github.com/jlopp/physical-bitcoin-attacks