Blendshapes

I used the cluster set up to create the blendshapes I needed. Looking at various tutorials, I found that the best way to do an eye blink blendshape was to also do in between shapes so that the eyelid rotates correctly around the eye rather than just passing straight through it to get to the final position. As I already had set up the clusters, it was very easy to just position the eyes how I wanted them then duplicate the mesh at that position. I made three in between shapes, plus the final closed position, making four in total for each eye. To set up a blendshape correctly with the in-between shapes, it is important to select them in the right order.

First select the in between shapes in order. So 1/4 closed, 1/2 closed then 3/4 closed.
Second select the final closed position.
Lastly select the deafult, main mesh.

Then go to create deformer and open up the blendshapes options. Check the In-between box, hit create.

Now when you open up your blendshapes, you should have a nice smooth blink.

To add the other eye, first select the closed position, then select the main default. Go to Edit deformers, blendshape, add. This will add the second eye blink to the list of blendshapes, but without the in-betweens. You need to add them after. For each in between, select it first, then the default and go to edit deformers, blendshapes and open up the options for add.

Check the add in-between target checkbox and type in the index number (if this is the second blendshape you've added, this number will be 2, third will be 3 etc). Next type in the in between weight value.

1/4 closed will be 0.25
1/2 closed will be 0.50
3/4 closed will be 0.75

As long as you put in the correct values for each inbetween, theywill be in the correct order.