Do you have any 4th of July tips for traveling with Uber and Lyft?

Manhattan has crazy number of rideshares and they are iterally overflowing on the streets.  Just go to any street corner in mid-town, and you will see black cars lining the curbs.  You can wave over any of them (even though you are not supposed to)

The traffic will ironically be light somewhat light, because people won't be working tomorrow. Remember, millions of people travel into Manhattan to work every day, and on the fourth of July, they won't be around.  An slightly increased tourist count won't dent that at all.

If you can afford the prices of Uber and taxis (compared to subways and buses), I do suggest you use them as much as you can.  I would avoid the busy times, say around the fireworks.  Those times can create surge pricing.   I am not sure if rain is in the forecast, but this city seems to get surges whenever it rains, as people rush to get a covered ride.

it'll be super hot tomorrow.  Taking the subway will be brutal, and many people faint on the platform.  Just watch out for that.  

There are plenty of Uber and Lyft.  Bazillion of them.  Way too many, and tomorrow is no exception.  Surges do happen, but not that often.  It's usually tied to very specific times and events.  If you see a sudden surge, just wait it out or walk a bit.  You can also fallback on taxis too.  Just raise your hand and hail.

NYC during a summer holiday is tough... best of luck to you