Common mistakes by beginner students of Spanish
I identified that the following were problematic for beginners students and made a list with explanations of the topics. Hope is helpful.
"Ir + a": http://www.studyspanish.com/lessons/ira.htm
Weather expression : http://www.studyspanish.com/lessons/wthrexp.htm
There is, there are -> Hay : http://www.studyspanish.com/lessons/hay.htm
Prepositions of place : http://spanish.about.com/od/prepositions/a/prepositions.htm
Prepositions "Por" vs "para" : http://www.studyspanish.com/lessons/porpara.htm
Most common prepositions : http://www.spanishdict.com/topics/show/9
Reflexive verbs: http://www.studyspanish.com/lessons/reflexive1.htm
Verb conjugation -> word reference
Noun agreement -> http://spanish.about.com/cs/forbeginners/a/adjective_agree.htm
Verb "Gustar" -> http://www.studyspanish.com/lessons/gustar.htm
Demostrative pronouns: http://spanish.about.com/od/pronouns/a/demonstrative_pronouns.htm
Ser vs Estar -> http://www.studyspanish.com/verbs/lessons/piserestar.htm
Definite and indefinite articles -> http://www.studyspanish.com/lessons/defart1.htm
Talking about age - http://spanish.about.com/od/idiomsandphrases/a/age.htm
Preposition "Cuando" - http://spanish.about.com/cs/grammar/qt/cuandoprep.htm