Mira

Roughly a quarter cup of active bug per litre is the usual starting point. Worth checking you were not thin on it.

Check the bottles before you blame the timing, because nice clip-tops are not all pressure bottles. If the gasket is perished or the bottle was made to look good rather than hold gas, the carbon dioxide leaves as fast as the yeast makes it and you will never get fizz no matter how long you wait.

Swing-tops made for carbonated drinks, or bottles designed for pressure. Mason jars and decorative bottles mostly do not hold it. Leave about an inch of headspace while you are at it.