Still trudging slowly through the original Hell Revealed. I want to play other WADs but am adamant I'm finishing this one; even if beating MAP24 right now makes me think I'll never be carved out of the right material for slaughter...
You can do it! Remember, not taking damage is always most important, even if it means to stop firing to focus completely on dodging oncoming projectiles, or to waste a little more ammo than you want to, or spend extra time on the map. You gotta protect that pretty face of yours.
It's not my playstyle in general, but I had to camp heavily to secure safety in MAP24 -- DoomWiki cites it as apparently the toughest map, so I guess I should soldier on; not long to go now, huh? :D