What influences when high or low tides will occur? What influences how high or low tides will be?

Proximity and positions of the Moon and Sun relative to Earth's surface at any point. If the Earth, Moon and Sun are inline (new or full moon) then the gravitational force combines to provide the maximum (spring) tide. When you have a half moon the tides are lowest (neap).

You also get effects of resonance which is basically amplification due to wave behaviour in the ocean basins and bays.

The position of the sun and moon determine the tides. Spring tide occurs when the sun and moon line up either on the same side of the earth or opposite sides. Neap tide is when the sun and moon are at right angles.

https://www.ducksters.com/science/earth_science/oc...

The Moon's Gravity and to a small extent the Sun's gravity.

the moon and gravity