Cementing Paste is very important to success in Ark Survival Evolved. Luckily there are a number of ways to make or raid cementing paste.
Craft your own
Cementing Paste can be made in the mortar and pestle, or the chemistry bench. It takes a lot of chitin/keratin and stone to make cementing paste. The ingredients are not that hard to come by, but it takes a lot of stone, which equals a lot of trips to harvest.
The Frog (Beelzebufo)
The frog collects harvests chitin from dead bugs and makes cementing paste at the same time, so it is a fantastic way to get cementing paste. Use the right mouse button, or the left trigger on console to harvest the most. The frog can only make paste from the little insects, not scorpions, mantis etc.
Raid Beaver Dams
My favorite way to get cementing paste is by raiding the inventory of beaver dams, but watch out for the beavers, they will rip your face off. Make sure to take everything out of the dam's inventory, so it breaks. If you only take out the cementing paste, the paste will never respawn, and the players on your server will hate you, or you will annoy yourself in single player. The dams will respawn like dinos.
These slimy guys make Achatina Paste, which works the same as cementing paste. They are a bit difficult to tame and keep, because they only eat sweet veggie cakes. After you tame one, put it on wandering and it will produce one paste every minute until the stack reaches 100, and then it will stop. Remove the stack and it will start to produce again. The snails will also poop out one achatina paste once in and awhile, but it is not worth waiting around for one at a time.