Monocrome flowers

Monocrome flowers - student project

I am brand new to watercolour.  I first made a single flower but found i had not made the varying shades different enough.  On a second try I did better but despite the fact that when wet there was darker areas, water pools etc that should have dried darker the finished product still looks flat, with none of the fun variation I love about watercolours.  Could this be due to me having cheaper paints?  I only have a value pack of tube paints from the art store, nothing fancy.