You have picked a great speech to deliver. My first suggestion to you would be to consider the context of this speech, and then to think, based on the context, about what props you could use to reinforce what Henry is actually trying to achieve through these lines. It is obviously a speech that he delivers before a very important battle, and he is trying to rouse the troops and give them hope and expectation of a victory. If we look at the speech carefully, reference is made to one prop that you could use. As Henry talks about how the names of those fighting today will be remembered, he makes reference to the "flowing cups" of those who will remember them. You could take in a tankard or something to emphasise this point.
However, a central theme of this speech is the concept of brotherhood that Henry refers to when he says:
We few, we happy few, we band of brothers;
For he today that sheds his blood with me
Shall be my brother...
You might like to think about what object could be used to highlight this important concept of brotherhood, that all of Henry's soldiers are fighting together as one equal team. Could you actually use other friends from your class as props and deliver the speech to them, embracing them as you say these lines to reinforce the way that Henry is trying to create a spirit of equity? Or could you use something like a string that you tie together as you say these lines to reinforce the idea of unity? Good luck, and I hope this gives you some ideas!
Augh! Shaketeach beat me to it! If you are stuck doing this in class without much room for really "fun" props, then definitely a cool crown and sword (both of which you can make yourself) are imperative. I also like your idea of the St. George flag (and maybe even a Coat of Arms) would be wonderful as well. However, and yes this isn't realistic but, ... I was just thinking if you could possibly come in on a real horse, ... whoa, that would really "wow" the crowd and present an interesting dynamic of the way the real Henry would have addressed his fellow soldiers. While Henry has a focus on camaraderie, the simple distance above the soldiers on foot does serve to cement his royalty. (Yes, I am imagining Kenneth Branagh here. It happens to be what impressed me about the scene on film.)
All good ideas.
Remember, Henry is a king. He has spend the night wrestling with his conscience. How can he ask men to fight and die for him? Henry V was a reluctant king but a great war leader.
There are two props I will suggest. The first is his crown, symbol of his right to call upon these men to fight and perhaps die for him.
The other would be his sword, the symbol of his war leader status.
I would suggest that you play around with your varius choices and choose the one with which you feel most comfortable.
I would use a sword. I like the flag idea, but that's taken. A sword is a symbol of power, but in this case is also a symbol of camaraderie. For the king to have a sword means he is also in the battle, and leading the battle right there with his men. It may seem trite, but I think a sword punctuates the speech well.
Basically, at the moment, I'm thinking about making a copy of the St. George flag and holding it up the way Henry would. I highly doubt that I would be allowed to use any of my friends as props. I was thinking of using something a little bit more practical eg. swords (but weaponry replicas aren't allowed). Such symbolic things would be a little to hard to do. Perhaps I could make a shield with the St. George flag on it?
Thanks for your detailed answer.