accurate native english phrases

http://dictionary.cambridge.org/results.asp?searchword=not+big&x=0&y=0

my friend went from average english to amazing english in 4 months by constantly checking this dictionary

barnes says:
so you read the dictionary then you suddenly remember
or would you practise
Gustavo says:
well, I read them and then I practise and make phrases...
barnes says:
in a document
or with people
Gustavo says:
both
luis joia says:
bom