An English Book

I usually use an online English dictionary to find out the meaning of an English word (2). No matter what I do, using a sort of a software, I think that I should change its interface language to English to improve my English skills (3)

NOTES:

(1): Necessary pause.

(2): It's implicit that you're try to find out the meaning of an english word, when you say that you're using an english dictionary. It's not necessary to repeat the word. 

(3): There is not clear idea. Maybe you should say: "I think that I should change the language of a software's interface, as a way to improve my skills on english"

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Read a book is an excellent idea. Make a new language as a part of you daily life is one of the best ways to learn. 

Have a nice day! ;)