If you go early in the morning (make use of the early entry for Harry Potter), and plan your big rides for first thing in the morning or later in the evening, you should be fine. Universal isn't THAT big, so over a period of 4 days you should be able to see and do everything you want, if you're a bit strategic in your planning.
Maybe catch a performance or two when ride lines get really long. There are always areas with manageable crowds, if you move away from the headliners. We happened up on the Jurassic Park playground, not planning to stay long, but my kids had a blast with the water guns mounted there, and got completely soaked (which might be fantastic in late July). Also, we found the wand ceremony lines were always really long at Olivander's early in the day, as people wanted to get their wands and start working the magic windows. However, there was no wait by mid afternoon, so it's a great attraction to visit when ride lines get excessive. Since you have multiple days, you wouldn't need to get your wands immediately.
Also, Universal is so compact that it's really easy to go back to the hotel midday for a swim or some downtime when the crowds are at peak. Disney transportation can make going back a hassle, but it's very simple at Universal. Universal also allows pool hopping, so you could try a different one each day.