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 pipe work with deposit build-up, perhaps lead or galvanized? Is your main stop open fully? Here is some general advice:
Often the problem will appear to be a pressure issue when it is a volume or flow issue. A restriction in a line or just having a long line or under sized line could be the problem. Call 1st Choice Plumbing at (770)596-5064