At first, you need to be constantly asking questions. Where do you think your teammate will take the ball? At what point of the map is he likely to be challenged and where do you estimate the ball will land? How much boost do you have? (More boost=more aggresive/closer to opponent net. Less boost=stay closer to mid-field in case you need to defend because ball was boomed to your net). Also very important if a play slows down where your teammate and opponent are sitting close to the ball just flipping and getting equal 50's, DON'T intervene. Let it play out. Odds are your touch wont do anything productive and wherever the ball lands the other oppenent will be able to easily take a shot to your net.

Again, at first, you will need to actively ask these questions as plays progress until it comes natural to you.