Watching the best football (soccer) team:

I´m watching to play to REAL MADRID play. In my opinion for me It´s they the best team of all time. (For me is fine, but it's quite informal sounding, so it depends on the situation - in my opinion, or something similar, is more common).

When I was younger I saw to play Zinedine Zidane play, with Ronaldo, Figo...and I couldn´t not fall in love with this team. (Couldn't not is a double negative, which makes it a positive - it works here, but when writing speaking or writing formally you should try to avoid a double negative. You can say 'I couldn't help but fall in love with this team). 

Now is playing in the the best player is playing for Real Madrid the best player, Cristiano Ronaldo. All Most people compare Ronaldo with Messi. Both are amazing footballers, but in my opinion I think that Cristiano is better than Messi (it's clear already) because he is a more most complete player. and Also, Messi has got behind Xavi and Iniesta behind him (you could also say in support), for this it´s more easy for he which makes it easier for him to score goals.

This season in the Spanish Leage (it's not wrong, but you can use the Spanish name - Liga BBVA. If you do then remove 'the' - This season in Liga BBVA) there are two new players, BALE (to Real Madrid) and Neymar (to Barcelona). I think that the league is going to be very interesting. (Maybe you can add that it's going to very exciting this season)

¡¡Hala Madrid!! Boo...I support Atletico!

It is good and I agree, that Real Madrid team with ZZ was special!