Making a spiral hand tied bouquet takes a bit of practice. I love this simple demonstration by Stephen Wicks. Take care that the flowers you need are trimmed, excess laterals removed from the bottom, thorns removed from the roses and the other supplies, such as the waxed cord and scissors, is close by for easy tying.
Notice that the stems are crossed at the bottom. You obtain this by rotating the bouquet in your hand after adding each flower (or greenery) stem. This causes the bouquet to round out naturally, rather than the stems sticking straight up and down, which begins to cause an unnatural bend in the flower stem which can result in snapped off flower heads.
Be sure to practice a few times before attempting this style of design. Learning as you go right before your wedding day can lead to frustration and stress if the flower designs are not coming out exactly as you imagine them.
Video by Authors of Simple Flower Arranging, Mark Welford and Stephen Wicks