Recursos y webs interesantes

Reverso (Spanish-English dictionary)

Diccionario de la Real Academia

Oxford Learner's Dictionary (English-English dictionary)

Cambridge Dictionary 

Burlingtonenglish (Your online textbook and more)

British Council Teens (Lots of resources for self-study)

Liveworksheets (More resources, different levels)

English for Everyone (Resources in PDF. Interesting)