I created this guide for myself while moving from softcore to hardcore. I read all the guides, tips, hints, etc. I could. Even with all that I still didn’t get it. I thought I was doing great when I reached Level 65 before I died then had to take another 6 heros before I could reach that again. It wasn’t until I decided to be INVINCIBLE that I blew past that into Paragon 150 territory playing at T6. Doesn’t sound very good, but . . . I haven’t died yet. 
There are four sections to this guide. It’s best to read them in order so they make sense and fit together. I’ve broken them into separate posts so you can skip ahead easier.
Game Philosophy
Game Preparation
Game Strategy
Specific Tips
Game Philosophy
First, the EASY WAY!! Start at the lowest “Normal” skill level and kill, destroy and open absolutely everything along the way. You’ll get to level 70 after a while. Just don’t try to improve your skill levels into rifts until you’re at level 70.
The mind set for softcore is different than hardcore. With a resurrecting hero you can charge in, kill as much as fast as you can, and when you die, oh, well, it’s back up in a few seconds. In hardcore you’re dead. You have to accept it will happen. Plan for it. Some suggest you stop for awhile to allow your emotions to calm down.
Another difference is perseverance. If you enjoy repetitive action games learning how to change strategies for return and improved progression, hardcore will work.
The thrill of walking the edge of death is exhilarating in softcore. In Hardcore it’s death, period. Anytime you feel tight, a little anxious, or less than SUPERHERO you’re in danger. Try this new refreshing attitude -INVINCIBILITY. Instead of feeling relief at having survived, feel empowered as you destroy even the worst monster with little stress.
A simple mantra is “Speed Kills -but- Kills Speed”, i.e. “Going fast will kill you -but- Purposely killing everything along the way will be faster than restarting at level 1 again”. Sweep everything up like a true warrior and clear everything you see. It will give you more points, better stats, more gear choices, faster kills in combat, more money and materials, and faster final growth by not having to restart.
Use the same warrior type until you reach level 70. Your continued practice will do more for your learning and fine tuning game play than any softcore development. Your mistakes become more meaningful and impressive. Plan on at least 5 heros going through the first testing, trial and error, and strategy development. After that work to grow a hero. However if you want the fast way, take it slow, build up your toughness, and get your mindset off softcore.
You can acknowledge the hero by putting him or her into the Fallen Hero’s tab under your Profile. This ONLY appears when you choose to “save” the first Fallen Hero. When you look at other players you envy, take a look at their profiles. You’ll be surprised how many of them DON’T have Fallen Heros which mean they never really tried to grow a Hardcore Hero. You are joining an elite club not all players are willing to risk.