Eight characters as a compatibility constraint
Some older systems enforce a short maximum. A uniformly random result with a broad character set is preferable to a name, date, word, or keyboard pattern, but length remains important.
Do not reuse a short password
A unique password limits the damage if one service is breached. Store the result securely and never use the same eight-character value on another account.
Use every accepted character group
If the system accepts symbols, numbers, and mixed-case letters, keep them enabled. If it rejects a group, turn only that group off and generate a fresh result.