I'm growing cut flowers for first time obelixx, I've found Sara Ravens website brilliant both for choice of seeds or plant plugs to buy and the information on how to grow them. It's a very inspiring website. The Higgledy Garden website is also packed full of info all told in a very tongue in cheek way. Seedaholic is also another good site for info and varieties. For xmas I was bought "The Cut Flower Patch" by Louise Curley which is excellent. It's full of practicle advice as to planning and siting your patch, suggesting best plants to grow, including planting plans. Also how to condition your plants after cutting to give them a longer vase life. Hope that helps.
Therse are the plants I will be sowing.
Foliage: ammi majus and ammi visnaga, and euphorbia oblongata
Flowers : cosmos various colours, larkspur, scabiosa,antirrhinum, agastache, zinnia, helianthus, various rudbeckias, dahlia bishops children, karma dahlia plants which are bred specially for the cut flower, nigella, calendula, and a few others if I can find the space! Great plants to attract bees too.