Alison Thompson
Patterns available as Ravelry Downloads
Crochet: Ornamental Flower
I have recommended a cotton 4ply however you can choose a thicker yarn to achieve a larger end result. Also, work with the hook size that suits your tension.
Crochet: Applique / Embellishment
This is an extremely flexible pattern and whilst I have mentioned some yarn types, you can pick and choose based on your own preference.