Hey Mauricio, I've made some minor corrections.. hope it helps..

First notebook entry: Introducing myself

Hi everyone, how you doing?>> how are you doing? 

My name is Mauricio and I am studying English and spanish, and I would like to improve my English level with your help, >> (you can do without 'level' here.)>> improve my English with your help

I think this page offers a very good opportunity to get real contact with native speakers.>> (you can say instead 'get in touch with')

On the other hand, I would like to help you with the topics related to Spanish, if you have questions do not doubt asking me. >> don't hesitate to ask me.

by the way, I'd love to get your help with Spanish. ^__^

First notebook entry: Introducing myself

Hi everyone, how ARE you doing? My name is Mauricio and I am studying English and spanish, and I would like to improve my English skills  with your help, I think that this page offers a very good opportunity to get A real contact with native speakers. Of others lands, I would like to help you , the topics related with Spanish, if you have questions,you  do not doubt ask to me.