I am certain jail broken devices have much greater flexibility in this regard but from a standard iOS perspective I would simply offer the basic settings that seem popular and appear to best save battery power.
1. Set brightness to manual and at about the halfway point of the slider. Adjust upward ony when lighting conditions warrant.
2. Manage location services so that you don't have dozens of apps constantly polling for this data.
3. Same logic to be applied for notification center to minimize application polling.
4. Identify then create keyboard shortcuts you will find most useful
Other members will surely add to this small list. While not tweaks in the purest sense of the word these tips do deliver rewards!
As I mentioned, and likely what keeps calling me to jailbreak my device, is the ability to truly tweak your iPad through various cydia supplied apps.
The most important rule regardless of whether your device is jail broken or not? HAVE FUN WITH YOUR NEW TOY!