Choose a container that will complement the shape and color scheme you have in mind. If you are just starting out, go with a traditional size vase __ not too tall, and not to squat. As a general rule, your container should be about one_third to one_half the size of your finished arrangement. So, for a vased bouquet you'll need mostly flowers with longer stems. A smaller bowl or basket is fine, too. You'll simply have to cut stems shorter and may need floral foam to help position each bloom. It helps to start with the simpler designs and work your way up, and a vased bouquet is often recommended for a first project.
Whichever way you decide to go with your flowers, a lovely idea is to try and tie your whole theme together so if you're going for roses, then have a rose design featured somewhere within your headdress. Look out for a company who can work with you and your designs and most importantly your budget to create that one_off, bespoke creation just for you.