know this is strictly on topic, but if you are not careful it will all go 'peer shaped.'
seriously, it does depend on medium, with watercolour it is possible to lift sunrays out after painting the clouds by carefully use of a damp brush or kitchen roll. It can be done on a dry painting by dampening the sky and using folded kitchen roll to lift straight sunrays.
Oil or acrylic is different and I would experiment with dry brush methods, gently brushing with only a very little bit of thick paint on your brush, masking out areas not to be painted if necessary with a bit of torn paper.
It is best to experiement on scraps of card or board rather than on a proper painting straight away, you learn a lot by experimenting and just trying things out.