考える and 思う: Considering something, thoughts, and wishes
Compare considering dinner or another person's position with a thought about tomorrow's weather or a wish to help a friend. Distinguish content and intention from completed cooking or help.
Considering dinner or another person's position
考える includes thinking or considering. Dinner after checking the refrigerator and another person's position are the stated objects of consideration.
「冷蔵庫の中身を見てから夕食を考える。」 (I decide what to make for dinner after looking in the refrigerator.) The Japanese sentence places considering dinner after looking in the refrigerator; this English translation says deciding what to make. Neither reports that dinner has been cooked or eaten.
A thought about weather and a wish to help
思う includes thinking. The weather example states a speaker's thought, while the friend example expresses a wish, so the thought's content matters.
「困っている友人を助けたいと思った。」 (I wanted to help my friend in trouble.) The wish was to help a friend in difficulty. The sentence does not also report actually providing help or resolving the friend's problem.
Separate the thought from a completed action
「明日は晴れると思う。」 (I think it will be sunny tomorrow.) This is a thought about tomorrow being sunny. It is not a reported observation of tomorrow's weather or a confirmed forecast result.
Dinner and another person's position are things to consider; the weather judgment and wish are stated contents of thought. Do not divide the verbs absolutely into rational versus emotional thought or make every 思う unsupported.
How does considering dinner after checking the refrigerator with 考える differ in focus from 明日は晴れると思う?
Show the answer and why
The first concerns dinner as something to consider after checking the available contents. The second states the speaker's thought that tomorrow will be sunny. Considering dinner does not report completed cooking, and the weather thought does not report a confirmed observation.