How do you increase water pressure in your house?

you can put in a circulating pump but you must find out how many gallons is your water heater (so not to suck all the hot water out) but a pump is your best bet. You got great answers especially about the air raiders which come off with a pair of pliers or channel locks (adjustables)

Try to locate the shut off for the entire house. It should be located near an outside wall and usually has a regulator located near it. Make sure that the main shutoff is fully opened. Also check the shut off at the meter. It should be fully opened as well. If neither of these solves the problem, then you could increase the pressure at the regulator. You will first need to buy a pressure tester though. They can be purchased at any home center. You don't want to randomly change the regulator setting without having a way to monitor the changes. Factory setting on a regulator is 50 psi by the way.

Does it just effect those two items? If it does it suggests a blockage or restriction of some sort. Are there any isolating valves on these locations if so check they are open if its actually the whole house affected check your main stop valve is fully open. This wont actually increase the pressure but it will increase the flow.

There is a normally a regulator in the supply line coming into the house. That can be adjusted to vary the water pressure. Some components of the water system may be susceptible to high pressure, toilet or sink valves etc. so check with a plumber.

depends upon your source of water, city vs well

also how old your pipes are, old iron pipes get restricted.

check that the nozzle on the sink is not clogged with junk.

CLR works if calcium buildups

Otherwise consult a plumber

Try turning all the water shutoff valves that you have to "full"...If that don't help, have your water company look at your water meter.....

Put the header tank in the loft - if the tank is at the same height as the shower, it will never be very strong. Alternatively put in a power shower with a pump.

remove the strainer on the kitchen faucet,

clean the shower head out,

Call a plumber .