The smaller person would be wise to try to avoid a 'strength' type grip strip, where you grab the hand and try to pull off the grip, strength versus strength rarely works for the smaller guy, we need to consider hitting the grip off. Less strength and more dynamic.
In the video above you will see how the sleeve is pulled down to take the slack out of it then as the shoulder is pulled back you slap off the grip. Make sure you are slapping in the direction of the weakest part of the grip.
When you have stripped the grip do NOT let them have the hand back or they will simply re-grip, palm their hand away setting up a clear path for you to take control.
The same with the no gi version. Attacking the weak part of the grip is something I was taught in traditional jiu jitsu but works equally well for Brazilian Jiu Jitsu.
The key to the grip break is timing, make sure you are working in synergy, every part works together.
Let me know how you get on.