Just understand that though you have read and researched it, nothing will prepare you for what will happen. Taking other psychedelics only helps people being comfortable in an altered state. But DMT happens so fast, that you'll wish it lasted longer, and you won't exactly have time to send yourself into a bad trip. Even though it will feel like an entire year shoved into a few minutes as you're in the trip, soon as you come out the time will fade.
Like: think of every minute you have lived in the past year. And how many minutes of it you actually remember? Very, very, very little. I look at a DMT trip the same way, so much happens, but you can only really remember glimpses of it.
Anywho, back on topic...
I think there are 3 things that account for a bad trip / bad time with any psychedelic and that is:
1. Taking TOO MUCH when you dose too high on something you've never done before, that will always put you in less control.
2. BAD SET AND SETTING - Always do it in a comfortable place, so you don't have to worry about outer problems entering into YOUR time.
3. Trip anxiety - I think this is the biggest one, I find what sends most people into bad trips is wanting it to be over before its gonna be over. As soon as you want it to end, you're gonna get nervous, and think about bad things, and just want it to stop and it snowballs from there.
So what is the solution? It is... and what I think matters the most to you my friend and anyone who first tries DMT:
DON'T HAVE ANY EXPECTATIONS, AND REALIZE THAT IT WILL DO WHATEVER IT WANTS TO DO.
Respect it, just be in the mentality that,"Show me whatever I you want me to see, and do to me whatever you want."
Don't hold onto anything, and realize you are NOT in control, and that you're gonna float down a raging rapid without an ounce of control.
When you truly do that, you wont have a bad trip, and it will be one of the most amazing introductions to psychedelics you'll ever have.
If you've been seeking it, then you should do it. The experience is thousands of times more special, and more real than any trip report, or any book can describe.
Good luck.