How can you increase water pressure?
This question is too general to answer in detail. There are a lot of considerations, e.g. do you have enough pressure at your mains? do you have old furred up pipework, perhaps lead or galv? Is your main stop open fully? Our general advice would be to give us a call so we can determine which solution works best for you.

Why would a toilet bowl suddenly go dry?
Here are opinions and answers from B&L:

Do you have any large, thirsty dogs?

There is really only one answer to this question. Poor venting or no venting of the fixture. vents allow for air flow to the toilet sewage system. without the vent air pockets are formed in the waste branches witch can cause what is called backsiphonage. the air in the system, which without a vent can only ecscape through the sewer, can pull the water in the trap of the toilet with it. It’s actually very simple but hard to explain. Hope I was of help!

Can you put eggs or eggshells in a garbage disposal?
Eggshells are very brittle and break as soon as the disposal is flipped on. You would be surprised what you can put down a disposal without doing any damage. Tip: Stay away from the outside of corn husks, and other stringy foods that may get tangled around the blade motor.

What is wrong when pipes make sound as you turn on the water?
Most likely your water pressure is too high, and the water flow is causing water hammer on your pipes at the turns.