deep, hard, serious
This topic requires a lot of deep thinking.

good
Yes, I'll email her instead—that's good thinking (= a good idea).

clear, logical, rational
muddled (esp. BrE)
quick
forward
The school would have made better use of the money with a little forward thinking.

positive
abstract, analytical, critical
creative, independent, innovative, original
lateral
wishful
His claims to be a millionaire are just wishful thinking.

piece (esp. BrE)
a brilliant piece of lateral thinking

do
We have some hard thinking to do before we agree to the plan.

apply, use
The book shows you how to apply critical thinking to your studies.

encourage, promote, stimulate
She believes in encouraging creative thinking in the classroom.
We hope that her book will stimulate thinking about this subject.

thinking behind
It was difficult to see what the thinking was behind their eventual decision.

contemporary, current, modern
fresh, new
conventional, old, traditional
divergent
government (esp. BrE)
The latest announcement marks a major shift in government thinking.

Labour, Republican, etc.
economic, historical, political, scientific, etc.
Traditional educational thinking placed importance on learning by rote.

feminist, socialist, etc.
military, strategic

develop, influence, shape
clarify, explain
change
They are unlikely to have changed their thinking so soon.

dominate
His writings on motorized warfare dominated strategic thinking in the 1930s.

in … thinking
contemporary trends in feminist thinking

thinking about, thinking on
What is the current party thinking on welfare benefits?

a shift in sb's thinking
There's been a shift in government thinking on genetically modified food.

to sb's way of thinking (= in sb's opinion)
To my way of thinking, it would just be a massive waste of money.