This is my workflow for portraits/headshots. I’m sure that I do other stuff than this but here is a general outline:

1. If needed, lighten exposure to see enough detail
2. Crop to desired shape.  Use Golden Rectangle.  Use Command-O  to change overlay.  Place a key element at ‘cross lines’.  Or have one of the vertical lines go up through centre of face, for example in a portrait.
3. Overall: I play with Exposure/Contrast/Clarity/Saturation to get the balance the way I like.  If I up the Clarity and Contrast almost always drop the Saturation. 
4. I’ll also play with the Highlights/Shadows/Whites/Blacks.  This can open up shadows and tone down the highlights if necessary. 
5. Eyes: Adjustment Brush (I bought Sean Archer’s Lens Lab add ons  for the Adjustment Brush.  They are really handy.  https://lenslab.com/products/sean-archer-collection)
6. Iris enhancement: If the eyes are pretty much evenly lit, I do both with same overlay.  If they have different amounts of light, I click ‘new’ for each iris.  Don’t overdo them but bring them up so that they can be seen.  If you are shooting outside and there is no ‘glint’ in the eye from a reflector, this will help with that. 
7. Dark edge of iris: Click ‘New’ on Adjustment Brush and go to ‘Darken’.  Use your mouse to make circle small.  (You can also use the square brackets for this [ ] to make bigger or smaller.  Sometimes better control of the size this way.) Go around the very edge of the iris, not going onto the white of the eye. 
8. Whiten eyes: Click ‘New’ on Adjustment Brush and click on ‘Lighten’.  Go over the white parts of the eyes.
9. Click ‘New’ again and use ‘Lash and Brow Sharpen’ 
10. Now but often later when I have done some other stuff, I may use ‘Lighten’, ‘Sharpen’ or ‘Clarity’ or a combination of more than on using a larger ‘circle’ over the whole eye/lid/brow area. 
11. Whiten Teeth with Adjustment Brush.  You can customize.
12. Lips: Use the LensLab colour of your choice.  Or just use Sharpen or Clarity
13. Spot removal brush to get rid of blemishes.  This can be done in PS as well but pretty easy to do in LR
14. Adjustment Brush: Soften skin or Soften Skin (light).  Depends on the skin.  Often ‘light’ is plenty.
15. Adjustment brush: Lighten - use this to highlight/accent hair.  Don’t over do.
16. Adjustment brush: Darken - Usually darken the background on portraits. Gradiently darker as it gets to the edges.  Do the whole background then hit ‘new’ leaving it on Darken and do further out in steps toward the edge.  You can also use Post-Crop Vignetting but using Darken Bruch gives you more control.
17. Detail: For sharpening the image.  Hold the Option button down on your Mac keyboard.  Then slide the ‘Masking’ slider to the right.  This will sharpen just the edges.  Once you have got that over to 60-70 or so, you can slide the ‘Amount’ over to the right.  You may not want to use this on all photos but it’s a good tool to have.
18. Make any other adjustments to Exposure/Clarity/etc like you did in step #3 and #4.
19. I will then sometimes use Clarity/Sharpen/Lighten in Adjustment Brush for some piece of clothing or something in the background I may want to bring out a bit. 
20. Photoshop: Go from LR to PS.  Use Liquify Tool to billow out the hair a bit on some of the ladies photos.
21. PhotoShop: Get rid of any background items that are distracting.