How to make the most of my first Coldplay concert?

Hey everyone! I've been lurking on this site for a couple of years but finally decided to make my own account so I can ask a question.

I am beyond thrilled to have the opportunity to see Coldplay for the first time this summer. This is a dream come true (seriously I can't even believe it) and I am eager to hear from experienced Coldplay concert goers so I can be prepared. I'm going to the Washington DC show at Fed Ex field in August. I have floor tickets (section B2, Row 1, about a third of the way down from the stage). Any thoughts on the quality of the show from these seats?

From what I've read, some venues allow people on the floor to stand closer to the stage. Does anyone know if Fed Ex field allows this, or do people generally stay in the vicinity of their seats? My main concern is knowing what time I need to get there and in line to enter the stadium. I don't want my "ok" seats to downgrade significantly because a thousand people get there before me and hence, stand in front of me, but I'm also not thrilled by the prospect of hours in line before the show! I just don't know what to do, but I want to get this right!

Can someone who is more experienced recommend a time that I plan to arrive at the stadium for the 6:00 pm show?

Any other hints or tips for a first-timer?

Thanks so much for all replies!