Write at a good pace. Don't slow the events down with really unnecessary descriptions, don't make them go too fast with excess time skips. 

Instance 1:

New boy walks in, bad girl loves him at first sight. Before the next class, they're already hitting at it in the boiler room. 

Instance 2:

The first day of high school... Literally, 5 seconds after reading 'My alarm went off', the next thing I see is 'And school ended so quickly'. 

(What the ratass happened to the grumpy Math teacher and the slender principal? Making new friends and so much more that happens on the first day!?) 

You have to make the story move at a good pace. The perfect pace to keep the readers engaged.