volitional + to omou ～おうと思う

"volitional + to omou" = "to intend to do such and such", "to think of doing such and such"

When talking about a third person, use "to omotte imasu."

ex. 今晩は薬を飲んで早く寝ようと思います。
Konban wa kusuri wo nonde hayaku neyou to omoimasu.
I think I will take some medicine and go to bed early tonight.

姉はアルバイトを探そうと思っています。
Ane wa arubaito wo sagasou to omotte imasu.
My older sister is thinking of looking for a part-time job.


Reference:
Schaum's Outline: Japanese Grammar