You stash your stuff somewhere? I ran into trouble (EDIT: Well, not "trouble", but it was a bit frustrating) because I was running out of space in my pack, but I didn't know what to leave behind. Keeping a stash sounds like a good idea, at least for things that you don't usually need immediately, like rings.
Sooner or later you'll run out of carrying capacity, either because you're lugging around too many items or because they're too heavy. It's also frustrating to be near the bottom of a branch and have to leave valuable items behind for other, even more valuable items. So it's a good idea to stash items you're not planning on using soon, but want to keep for later. In earlier versions of Crawl, it was important to keep track of where you left your stuff; in Stone Soup you can use Ctrl-F to find it and autotravel to reach it. The Eucumenical Temple is a good place for stashing items since there are no monsters there that can wander off with them. Lair:2 is a good place because only unintelligent, non-corroding animals are generated there, so no-one's going to steal or destroy your stuff.
You should of done lair. You were too weak to go so deep in the dungeon. Poison resist is not that important in lair for a MiBe. I have cleaned snake with a MiBe without poison resist. If you had a flaming weapon or a mace you could also of attempted swamp. Any axe wielder should be carrying a mace or flaming weapon anyway.
You're right, and I probably shouldn't have said poison resistance is needed for the Lair. It can be done without, as long as you're not exploring at 25% health. I've never survived the Swamp or the Snake Pit without it though. I often investigate the upper levels of a branch, but if I'm having trouble clearing them, I'll leave and come back later.
In general I think it's good to set intermediate goals. The early goals are usually the same. Find the Temple first, and pick a deity if you don't have one. Find the Lair, and clear it. Go back up to the Orcish Mines, and clear them. Then take on the Hive and the Swamp, in any order, maybe clearing the upper levels of both to gain experience. Get the Decaying Rune from the Swamp. Clear he Snake Pit, and get the Serpentine Rune. Clear the Slime Pits if you have corrosion resistance.
I usually don't make it that far, but if I do, I'm inexperienced and undecided. Clear the upper levels of the Vault and the Elven Halls. Don't go for the runes just yet. Visit the Hall of Blades if you're strong enough to survive the Abyss for a while. Visit the crypt if you have warding and some means to handle undead. Depending on your resistances, you may even need to start exploring branches of Hell before finally being able to get the runes from the Elven Halls and the Vault. After that, I have nothing to contribute. You can probably dive into the Realm of Zot and go for the Orb, and survive. If you do, don't expect to visit the remaining branches afterwards.
Something strange happened with this char.. On D:4 pretty heavy monsters appeared at the staircase. (Orc Priest with some friends) I managed to fend off and started exploring and I found a weird glowing room with a staircase that looked like a shop, saying "A staircase covered with sand.." I didn't dare to enter and kept clearing out the floor. I returned after levling up twice, and the staircase was gone.. :/ I have seen the Labyrinth before, but then the staircase was named "The Labyrinth". I guess I should've went in.
Occasionally some side levels pop up, and I think their entrances have been made temporary in Stone Soup. They're meant to be high-risk, now-or-never challenges. Labyrinths are mazes guarded by a minotaur with some very good items at exit near the center. If you're carrying enough food, and you can take a beating in melee, it's worth trying. I've visited several Labyrinths and never died there. I've also seen Tombs or Crypts (other than the branch) populated with undead; I haven't explored these since I always lacked the experience I think they require. I've also heard there are bazaars, with lots of shops, where you can go on a shopping spree just once; I've never actually found one.
Have you tried Deep Dwarf Berserker? 
Berserker with some staffs and the ability to trade off 1mp for recharging a staff/wand! Pretty interesting along with berserker.
I haven't played any of the new races, but I'll give the Deep Dwarf a shot. Not being able to regenerate doesn't sound too appealing, but perhaps with Trog's regeneration it isn't as bad as it sounds.
