Whenever I post running advice I give the disclaimer I trained under the guidance of JK. I have no experience at the elite level and this based on college running .
It is true you need to learn how to "run by feel." It is ok to check your watch for reasons of curiosity but even then you can mentally trick yourself into trying to hit a certain pace. Do not aim for a specific pace and do not feel pressured to run a certain pace if you have a group with you.
Understand the difference in feel between a "high end" pace and a "tempo pace." Both are at a certain threshold in your body . High end you should be able to speak a conversation and finish feeling you can almost run the workout again . Tempo you should not feel like your forcing anything , you will definitely need to focus , and you should finish feeling like you could do a few more kilometers .
For an average college runner , I observed high end to be between 5:40 and 6:10. Tempo would be between 5:10 and 5:25. Again the pace is really by feel , different at different points in the season, and I know faster runners who had faster paces .
Based on my observation and experiences , do not force any of these runs if you feel like crap and this makes the workout counterproductive . Also, when you truly learn to run by feel, you will find on some days your pace may be a little slower than the last time you ran the high end or tempo . This is ok and if it feels good then run the workout and don't be concerned with the pace .
I find it is in these times where some runners see they are running slower than a previous workout and then force a faster pace and then ruin the current days workout . If it's a 4-8 mile high end or tempo you may run the first 75% at a pace Slower than the last workout but if you maintain the "run by feel" you may feel great the last 15, 10, and even 5% and reach a fast pace that feels natural and super comfortable because you listened to your body the whole way. In this case your workout was a success despite a slower pace in the beginning areas of the workout .
If you are given a 5 mile tempo , for example , and your last mile is slower then the previous miles because you are too tired from forcing a pace earlier then I would argue you have failed the workout .
My post is simplified and the other variable of the distance of workout and if it's a progression run versus long / short threshold reps changes the pace but overall the approach to "run by feel" is the same.
Master the high and and tempo runs by feel and you will be a very good runner . Internalize the feeling of being at the threshold and be in touch with your body .
I knew runners, including myself, who claimed to run by feel and I even convinced myself I was running by feel for about 2 years of my training before realizing I was still doing it wrong and subconsciously trying to hit specific paces.
Please someone challenge my observations if they are wrong somewhere . I write based on what I learned from JK and my own experiences and am not an elite runner .