You have two options:
First, speed up iOS 8: end multiple tasks; clear junk file; delete apps; delete text messages, photos, videos, etc.
Second, downgrade your iPad from iOS 8 to iOS 7, BUT do it quickly. A few days later, the way is not available any longer:
1. Download iOS 7.1.2 firmware for your iPad 2. (just google it)
2. Make sure you have install the latest version of iTunes.
3. Connect your iPad to computer via a USB cable.
4. After detected, your iPad will be shown in the left column. Click your iPad to show the control panel.
Note: Make sure you have backups of your iPad. if not, backup it now.
5. Under Summary tab, hold on Shift key in Windows(Option key in Mac ) click Restore iPhone....
6. In the pop-up window, find the firmware on your computer and click Open.
7. Then, iTunes will downgrade your iPad to iOS 7.1.2.