Continue improving diplomatic relations with visits and parties. Eventually, we will probably merge the tribes, but for now they're new and both probably see the other as something scary and curious, definitely not as a self. Still, the feast should have helped enormously.
What we should work on right now as a tribe is the prerequisites for a city, which is to say, agriculture. It's risky bidness though; if the crops fail, we have to have enough food to keep going a whole year without growing any food. With that thought, our next objective is mass hunting and/or domestication.
Have a few tribesmen work on making a few tactics for catching a whole herd or most of a herd of gazelle. Only the tactics though, as we don't want to over-hunt and extinct them, at least not yet. If we have the man power, I also would like to suggest we gather a group of people to work on finding out how to live with animals close by. Look for fat, slow animals that would benefit from the protection we give them, or smart animals we can use to help hunt and keep vermin away from the stockpiles.
We should also find saltwater. I think we're next to a lake, but it could be an ocean, I'm not sure. We need some sort of pottery to extract the salt from the water, but once we do we can store meat for much longer periods of time. Jerky!