grab a plain white cup and saucer and have a go at drawing the cup to start with, don't worry if you think it's not right, do it again and again!! most artists draw/paint same subject over and over and over!! We should too!!
draw cup and saucer from different angles and different heights but keep everything quite small - on your paper, cup should be no more than half the size of the actual!!
the really cool thing about pencil sketching for watercolour painters is the similarity of process - painting/sketching from light to dark and building up layers of value to describe form and light!!
ciao ciao cari amici!