Sky is everywhere - you needn't even go outside, just step to the nearest window - which makes it easy. Sky is everywhere - how on earth does one decide which part of sky to photograph - which makes it hard. If you don't have a tree or a building or a kite you have no sense of scale. If there are no clouds (I live in Washington State - grey skies are normal here) then the picture becomes about the tree or the building or the kite rather than the sky.
Fortunately, June in Washington does provide a lot of 'blue sky with clouds' days so I had enough opportunities. Towards the end of the month I traveled to Montana, the Big Sky Country and I was overwhelmed with sky!