Don't be scared of lotion making! Yes, failure is a possibility, but if you start with a good recipe, use enough of an appropriate emulsifier, and follow good manufacturing processes, it's almost a guarantee you'll create an awesome lotion that won't separate. Remember that a good lotion requires three things to emulsify - heat, mixing, and chemistry.
When it comes to working with volume measurements...is tablespoon of beeswax before or after heating? Is the coconut oil melted or not? We use weighted measurements because they are way more accurate. Plus, you have the bonus of not having to wash measuring cups and spoons afterwards!
You want to follow good manufacturing processes, which is to say you will heat and hold. This is a simple idea - heat and hold your heated oil phase and heated water phase in separate containers for 20 minutes at 70˚C or 158˚F - but it goes a long way in creating a stable, well emulsified lotion.
And you want to mix your product. Most of the time, you can use a stick blender or hand mixer, unless your emulsifier indicates otherwise. (I'm looking at you, Montanov 68!) There is some debate about how long to mix your product. Generally, I mix for about 3 to 5 minutes, then let it cool, add the cool down phase, and mix again for another minute or two. It's hard to overmix your product - Olivem 1000 notes you can overmix it - but this amount of mixing works for me.
If you want to make a lotion for the first time, may I suggest the post let's make a lotion? I can guarantee that if you follow this recipe, heat and hold, and mix well, you will have a great lotion that won't separate. (If you're using Optiphen, there's always a chance of failure. See this post for more information...) Or check out some of the other recipes in the newbie section!