Use a direct destination when possible
For websites and social profiles, encode the final public destination rather than an unnecessary redirect. A label can identify your download without changing what the QR opens.
Structured QR types save steps
Wi-Fi QR codes can carry the network name, security type and password. Contact QR codes can use vCard data so supported phones can offer to save the contact directly.
Print quality matters
Keep a quiet zone around the code, preserve strong contrast and test the final printed size with more than one phone before producing a large batch.