i decided to draw an easy flower, like a kind of orchid (they aren t 'real' orchids, they are painted with a little bit of fantasy, put the principle for real orchids s the same ;) ).
at first you have to draw the outlines.
just make a pentagon and a little kite in the middle.

now paint the petals.
they needn t to be perfect now.

now paint the hopper

at next you need the shadows.
draw the lines from the outside to the inside, so that they get from big to smal.
the first shadows should be grey.

the second shadows are black. paint them a bit littler than the grey ones.

every flower needs a stalk.
make two lines, but they shouldn t be straight! that looks unnatural.

<- draw some lines like this.
but not all over the stalk! just at some placements.
fill the empty gaps with grey.

then it looks like this.

you can add as many buds and flowers, as you want :)