I've just started to learn the macro style. It's really disrupting my play style - any tips on learning how to use this style of play?
Day has lots of dailies where he talks about specifically this or more generally about learning any particular thing. Well worth a look.
His main point is to get comfortable with losing games where you are training since you aren't training for the five games today but the fifty games after today.
One example for practicing your macro would be to play five games in a row where ALL that you are focusing on is constantly building workers, never being supply blocked and always having low money (or even just one thing!). If during these training games you get attacked - don't worry, just keep focusing on those three things and deal with the attack only if it doesn't break that focus - EVEN if it costs you a game!
The idea is that these training games with a dedicated focus should make the things you are training second nature, so that afterwards you don't even need to think about them.
Macro play is the foundation of SC2. After you know how to handle macro then you can get fancy and cheesy. Because if your cheese fails, you need to be able to move on and recover!
There's a lot of variables: Observer your opponent, is he mounting an attack? No. Expand! Try to expand every 5 minutes and build workers. Keep observing your opponent. If he is mounting an attack, prepare some defense and get ready but don't over do it.
A few minutes later, you get so much money you won't even know how to spend it. The key at this point is to know how to macro your production. (put a shortcut on those barracks on those queens, on those gateways!)
If you have good macro, you will climb the later pretty well.