Read good books and observe closely. Also, read up some popular blogs. This will hopefully serve as a good input.

Further, read up popular questions on Stack Overflow within your area of competence and offer your perspective. This will do two things a)- give you confidence that you're writing something for which audience exists b)- improve your understanding of issues as well as you write.

Please take this with a grain of salt since I'm not a good writer myself nor have a popular blog :)