Logging into your SPG Dashboard, you can take a look at your current offers available for you. I checked and found that there was currently a targeted offer available, where you could earn 250 bonus Starpoints for booking a start through the SPG app. You can download the newly updated SPG App for your iPhone and Android devices.
Earn 250 Bonus Starpoints With New Booking (Targeted)
An eligible member can earn 250 Starpoints for completing a stay that was booked using the SPG app. The booking must be made by Jul-01-2017 and the qualifying stay must be completed by Jul-01-2017.
Bonus Starpoints can take up to 2 to 4 weeks to post to your account after confirmation that you have completed your stay.