I blazed through up until level 54 and now it seems anything one shots me. I know dex is what im supposed to be stacking, but is there something else i might be missing?

All resist + one resist with the "One with Everything" passive works wonders for your EHP.

This might be what the guy above was saying but, what I do is stack one thing... Fire (it can be anything though- physical resistance would likely be best since you always need it in melee) and I also try to get resist to all on those items that give me fire as well. Then you use "one with everything" as your passive and it works very well. I might switch from fire to something else once they nerf fire chains, etc. though. Hope that all makes sense. Good luck!

@54 I would just get high exp + at the min. 19% bonus exp from helm and just join a pub. Yes you will still die a lot but once you make it to act 3, you will find that most parties will have at least 1 lvl 60 with decent gear that can carry the team to max level. I have maxed chars as fast as 29 hours in a mix of pubs and early solos. I also don't recommend going dual wielding if you find yourself dying often. Should just aim for high vit + shield and use any skills that helps reduce damage, then buy some decent level 60 gear and work from there.

believe it or not I found that AH has some really good deals on gear. find the specs you want (resist, DPS, Dex, Vit and/or specialized skillset i.ie. Life on Hit) and set your price limit in the bottom left box by the search button. found an amazing chest for only 7k that lasted to inferno.

Look for Level 60 gear (ilevel 61 to 63) in the AH with Reduced Level requirements. I believe level reduction goes all the way down to -15 levels which means Level 45 characters can use them, and provided a great boost to my survivability when levelling to 60.