By AoM you mean Angel of Marksmanship, right? Sometimes people write AoM for Angel of Masochism.
On Angel of Marksmanship I go SoG, SoG, Dualgunner, EE, SoG, EE--sometimes taking the EE earlier, depending on the game. After that I go with some levels of SoB if I have found a good artifact pistol like the Beretta and not many mods, or two levels of Finesse and then Whizkid if I have found enough good (damage is best, speed comes next) mods that my advanced pistol is getting nearly full of mods. Once you get SoG*3, Dualgunner, and EE*2, you're set up to be deadly enough that you won't need TaN or Ironman traits, since you're probably going to be at least as deadly as a chaingun-based character until the end of the game.
For purposes of learning to play DoomRL well, it helped me a lot to play some games where I got Intuition*3, though, and learned to kill things without seeing them. For Angel of Marksmanship you could try SoG, SoG, Dualgunner, EE, SoG, EE, and then three levels of Intuition--you would get to play the last few levels of the game with Int*3 in this way. Or you could play a non-challenge game, get the chaingun ASAP, and play EE, EE, and then immediately three levels of Intuition. You will need to pick up all the ammo you can find (this kind of "blind-fighting" uses a lot of ammo), but learning to fight monsters that are outside your field of vision is very valuable. After that, you will learn to do it without the third level of Intuition, by listening (with stereo headphones) to what direction monsters are coming from, and then firing into spaces they might be in that you can't see--you will hear their "pain" noise when you hit. With some practice this becomes a very valuable technique and you won't need to invest three levels of traits into Intuition to do it.
Blade often takes a level of Cateye in his posted games. I haven't found this so useful but Blade is a much better player than I am, maybe he can explain how it's useful.
Anyway, Angel of Marksmanship is much easier once you have some practice at killing monsters before you see them.