Please give me some tips to learn English prepositions?
When i speak or write English i do not have problems to use them. but when teacher in yhe school ask me about, i am not sure in the right answer.
How can i practice and be better in this?
Using images and sentences in context helps a lot.
BTW, the correct form for your title is "How did you learn.....?" Learnt is the past participle [emoji]
When I was in elementary school, our teacher told us that a preposition is "Anything that a squirrel can do to a tree or an airplane can do to a cloud". To, from, around, by, through, over, under, etc.
I don't know if that helps you any, but it helped us recognize them.
There're a lot of resources which you can use to improve: BBC learning, a book entitled "English Grammar in Use" and other sites on the internet. I think that the best way to learn is practice. There're some rules you will find useful to learn.