HOW TO GET RID OF A SPINO:

Pretty easy at high levels but that's not why you're reading this anyway. At low level you probably lack the fire power to take one out and the cliff and bow tactic won't work, because they're fast and you won't be able to hit them. Try and make a trap instead:

Place a wooden spike wall.

Place a fence foundation behind it.

Place 2 walls on the foundation.

Expand to the sides the same way.

Spinos are stupid so it will run straight at you and die from its own damage. You can also shoot it from afar as it will be attacking the spikes and not you. Improvise. Adapt. Overcome!