There are anti-glare films that can help a little. But not much can be done if you are out in bright sun: the backlit LCD is just no match for it.
As I live in Arizona we pretty much have bright sun every single day. So considering ereaders have gotten so inexpensive I bought a Kindle which does great in sunlight. Alas it's interface felt very last-century so I returned it for a Nook Simple Touch--which was a much better choice for an iPad owner as it has the same kind of touch interface.
But you should be able to get better results with the iPad with an anti-glare film It won't brighten the screen but will help a lot with the glare.
Michael