HELP ME with my centerpiece!!!!

You're going to have to be brave enough to start all over again, and it will require a few materials as well as cutting down those stems.

Professionally constructed centerpieces have their full look because they do not rely on the neck of the vase for shaping. You'll need a few items -- I'm linking a tutorial for you to look at. The easiest thing I would suggest for you is a styrofoam filled bouquet holder. You drop that in your vase and then begin inserting greenery (first) and then the cut roses (second). There are drop in dishes, styrofoam pieces, and floral tape that would work, but I think the bouquet holder would be easiest for you.

It looks like you have 10 roses in the arrangement. Place five around the base of the holder -- right above the lip of the vase. Space them evenly. Next row, use four. Then put one rose at the top of the holder.

If you do it this way, you will have a vase without all of the stems showing and much more control over the shape of your design. The sticks? Don't spread them out as much, and cut them back. They shouldn't be any taller than your vase (preferably a little shorter). If you really like the sticks, consider buying a bunch of curly willow. It will give it a more polished look (they're cheap -- it won't break the bank).

http://www.wedding-flowers-and-reception-ideas.com/tall-centerpieces.html

Centerpiece, I'm glad you answered -- because I didn't know where to start!

As long as she buys a few stems to practice with, she can knock these out. It'll take a few times, but she'll get it.

What would I use inside of the vase to cover the bouquet holder part?

Unless you plan on hanging some ivy pieces around the base of the bouquet holder, the stem of the holder will show. You have a few options. I would suggest you use a frosting spray paint made by Valspar. It will lightly frost your vases and hide the stem. Here's a link (Ignore the feathers -- the point is that the person putting together the arrangements was using the bouquet holder technique and needed to hide the stem. It's very easy to do -- light coats):

http://shannonberrey.com/_blog/Shannon_Berrey_Design_Blog/post/How_to_make_feather_centerpieces/

They also make clear handled holders, and while they won't really be noticeable in a dimly lit reception room, they are more expensive than the white holders.

If neither of these ideas work for you, you'll have to employ the bowl, styroam, floral tape, and floral clay method. It's not hard -- it's just that the other method is easier -- all self contained. You should probably get styrofoam balls. Slice off the bottom so that the ball fits neatly onto the dish. Take floral tape (It sticks to itself) and wrap the ball and the bowl until you get a firm hold. You use the floral clay to make a seal between the lip of the vase and the bottom of the bowl. Try it once to be sure you know how much you need to get a firm hold, but you'll want to transport the vases and the finished floral pieces separately and reset them at the venue (much easier to transport them that way). Then start your arranging. Point some of you greenery in the bottom row at a downward angle, then proceed normally. These are the products you'll need:

http://www.directfloral.com/p-453061561-oasis-lomey-6-design-bowl-clear.aspx

http://shop.hobbylobby.com/products/5-green-styrofoam-ball-172890/

http://shop.hobbylobby.com/products/moss-green-floral-stem-wrapping-tape-672410/#tab-customer_reviews

http://www.weddingflowersandreceptionideas.com/florist-clay.html

A florist here uses large leaves (fern, banana leaf, etc) to disguise the stem holder

hope that helps!

@ The Centerpiece Flowers - Thanks for the tips...i may not be the OP but your instructions are easy to follow. This is great education for a 'DIYer' like myself.

No problem.