Distinguish personal impressions, beliefs and considered opinions with realistic examples.
Synes for impressions and judgements
Synes is useful for a personal evaluation of an experience or object. Choose it when describing your impression or assessment, rather than inserting it into every opinion sentence.
Jeg synes at denne boka er interessant.
I find this book interesting.
Tror for a belief or expectation
Tror can express a belief about a fact or an expectation. If you are estimating a time rather than knowing it, tror avoids claiming certainty. Distinguish believing something from knowing it.
Jeg tror at bussen kommer snart.
I think the bus will arrive soon.
Mener for a position or intention
Mener appears in opinions and also means mean or intend, as in What do you mean? The boundaries between opinion verbs are not absolute, but comparing them helps match your intended meaning.
Jeg mener at skolen bør starte senere. Hva mener du med det?
The first states an opinion; the second asks about meaning.
Try it yourself
Write an impression of a film, a weather expectation and an opinion about studying. Avoid choosing the same verb automatically.