The book I read to research this post was Teach Yourself Flower Arranging by Judith Blacklock which is a very good book which I bought from a secondhand bookstore. Flower Arranging is a skill where it's quite easy to learn the basics but it takes quite a bit of practice to get really good at it. It's a good idea to become really good friends with your local florist and get them to put by some choice plants for you. A lot of people get there flowers etc from a local market store which can be good value but make sure the flowers and plants are fresh. A good flower arrangement can last for up to 2 weeks. You will normally use florists foam which allows you to insert flowers at any angle and keeps them in place. They use something called frogs to hold the foam in place. You can water the plants and flowers but some plants get water logged so it might be an idea to use plant food which a florist will often give you a small amount for nothing if you are buying flowers. You need some kind of holder for the plants to go in. I think hanging baskets are nice. You will have a focal layer which will be the flowers or sometimes berries and lower down you will have a filler layer which will often be leaves and branches. The focal layer is what you will tend to notice. The filler layer shouldn't be loud. This book gives you all the basics of this quite interesting hobby and there are plenty of examples of plants you can use. It's about what stuff is available in Britain and it's surprising what can be gathered in the countryside. You should never take plants by the roots and be careful they're not rare.