How has Japan succeeded aganinst the odds?

I am 14 years old and currently doing an assessment at school on Japan and how it succeeded against the odds! I was wondering if anyone can help me! I have got to answer the following questions:
Why is there such a lack of space ?
How does Japan manage to produce food with a lack of flat farmland ?
How does Japan pay for all the imports ?
Why is the road and railway building so difficult in Japan ?

Can someone please help me!