Ask HN: Any tips on database design (schemas)?

For example:

- Is it better to create fewer, but larger tables over lots of small tables? Does one approach give you faster speed? Or does it not matter?

- Is it a good or bad thing to add tables to your database design even if those tables are not immediately needed? For example, adding features that you may (or not!) implement in the future. Is it easier to add these features to your database design at the start (call it foresight!) rather than modify the database design in the future?

Any wisdom on the above, or indeed any tips you've attained from creating database designs/schemas is much appreciated. Thank you.