Grammar isn't my favorite part of teaching Spanish, but it's important to understand the structures and "rules" of any language you're learning.

I highly recommend the following sites: 

StudySpanish (great grammar explanations & other resources)
WordReference (a language dictionary and forum with many additional features) 
¡Conjuguemos! (an online game for practicing verb conjugations)

I've also compiled a few resources here that I've created over the years... 

Presente 
Presente Perfecto 
Pretérito 
Imperfecto 
Futuro 
Condicional 

If there is a structure you would like me to explain here, please send me your request.