Lunar phases aren't actually caused by the moon changing shape. It's caused by the moon changing position. As Earth rotates around the sun, it casts shadows on the moon, creating the eight different moon phases.
A tide is the rising and falling of sea levels. The tide varies based on the moon waning or waxing. The higher tides are called spring tides while the low tides are called leap tides.
Spring tides happen during waxing moon phases, but neap tides happen during waning moon phases.