To absorb the most information and yet let your brain rest a bit, it's better to follow this method: 25 minutes of hard work, then a 5-minute break. Every third break should last 20 minutes.
To remember something, let your kid read it out loud and clear, not paying attention to the speed.
If something's always taking your kids' attention away from their studies, play some quiet instrumental music in the background, like this: Hans Zimmer - Pandora.
Remembering a new schedule is always difficult. Take a picture of it, and set it as the wallpaper on your kid's phone. This way, when they look at its screen they'll see their timetable and have no trouble remembering it.
A 10- to 20-minute walk before studies will make the blood run faster and the brain work better. A morning walk before school is a great option.
To read something faster, read only the first and the last paragraphs.
It's been scientifically proven that mint stimulates the brain and improves concentration. You can also chew some gum or eat a mint sweet. Put some into your kid's schoolbag.
Some subjects are better learned through documentaries, like history or biology.

16 tricks that will make your kids’ studies fun and easy