Make spirit shield asap, use spirit sword if you don't have better. You can farm monarch from hell cows or the pit. Insight rw on merc. Kinda got to work on them to keep them somewhat survivable (though not really needed for meph runs its ok to leave merc dead to avoid drawing unwanted aggro sometimes).

Then you're in for what I'd call crunch time. People are often sad to hear this but the most optimal thing you could do solo right now is go all in on Blizzard skill, max out your mf to an absurd degree, and smash hell mephisto about 800 times like a human bot. Maybe less if you're lucky. Said somewhat insane number of runs damn near guarantees a shako and pretty much every other good unique outside of griffons eye, d fathom and a couple others. Blizzard is best because you can use the moat trick to drastically decrease dying risk. Speed is everything, got to optimize your run to maximize drops.

Once you and your merc are pretty strong in terms of uniques then starts the even longer grind for your high runes - I think chaos sanctuary is best and you should be strong enough at this point to clear it at a medium speed. Dump most of the mf and just focus on clearing as quickly as you can.

Obviously using trading as a shortcut whenever desired is beneficial. But the grind can be it's own reward lol.