Take a small piece of watercolour paper - around 7cm square. There are many varieties of watercolour paper but, for this design, all that is needed is a pretty heavyweight student quality paper which can be purchased as a single sheet or in a pad - either way, you will get many cards out of it so it proves to be excellant value for money.
Draw a simple flower shape in pencil and go over the lines with Tulip 3D paint - making sure that the chosen colour of the paint will tie in with the papers you have chosen. It does not matter if the lines are 'wonky' - there is no need to be too precise.
When the Tulip paint is dry, wet the paper inside one of the petals. Onto the wet petal, drip in some diluted watercolour paint. For deeper colour, add in a second drop of less diluted paint. Let the paint bleed around the petal and do not work into it. Repeat for the other petals and the centre and leave somewhere flat to dry.
Student quality watercolour is fine for this project and individual half-pans - or blocks - of watercolour can be bought for just £1.50 each so won't break the bank!
When the watercolour is dry, cut out the flower.
Take a piece of card of your choice ( I have used core-dinations) and cut to the same size as the front of a card-blank of your choice. Choose two co-ordinating backing papers, cut one slightly bigger than the flower and the other slightly bigger still. Glue in place.
Stamp, emboss or attach a sentiment sticker with a message of your choice.