Any middle / late game tips?

Recently I find out that when I'm now absolutely motivated (that happens when I'm wining a match 1v1 or 2v1 , and it's something I'm really interest in) I suck in middle o and late game I iddle my TC, I also have my eco unbalanced and my resourses have the weird tendence to float 11 11 11. I thought start by facing the IA only when I get castle age, because when I flush drush or trush I win 90% of times at least in moderate, also hard, I say 75%. Any tips? IA? Or whatever. I can follow an BO very good, but then...... I truly suck