I can't give any better advice than already given by others on the techniques for clearing.
However I too suffered anxiety for mask clearing. My initial attempts in the pool during OW went fine, but the next day I just got flustered. I allowed this to take control of me, so much so that for my first 100 dives I would allow the mask to fog up so it was nearly opaque before clearing. In the end I had to man up to myself, like you I reached out here and to other experienced buddies. I found by talking that my anxieties were normal, learnt to relax and the problem went away.
I still don't like it, and would not enjoy having to do a mask off swim (he gulf waters are quite saline) , but I can do it with ease.
Try not to fret about it, take it slowly, give yourself mental or physical rewards every time you complete it, don't beat yourself up if you don't.
Most importantly don't let it control you as I once did (you'll soon wonder why you thought it was so difficult)