any tips on staying alive?

I've found that being patient and being constantly aware of your surroundings helps. Even without God armor, you can survive if you are careful and know about what you're getting yourself into. Getting God equipment should be a goal, that way you don't have to stress as much.  However, even with God armor, you shouldn't just go headstrong into something without knowing what might happen to you.

Consider taking lots of food; Gapples for emergencies and water buckets for... Well, fire.
Always helps!

General Tips
- Pay attention! Know where the mobs are and only attack unless you need to.
- Don't go into a fight unless you know its within your capabilities. Your equipment plays a role in this too, for example, If you are confronted by a ghast and don't have a bow on hand then you are obviously not capable of handling a ghast - run.
- If you know you can't handle a fight anymore just run, its not like your going to be pointed as a coward for running or anything.
- Keep your Sword/Bow on a hotkey you can easily reach so you can switch to it easily.
- The area I live in is not lit up at all so I always carry a shield around, equip a shield if you need to!
- Where ever you are going you should know what you are facing there not just mob threats but environmental once too. Going to a mineshaft? Prepare to face poisonous spiders, take milk with you perhaps. Going to the Nether? Take a bow against Ghasts, a fire resist potion for obvious reasons. Going to go Slime hunting in Swamp? Take a sword with sweeping edge, to deal with the slimes splitting up better.


Mob Specific Tips (melee only) (Surface world only)
- Zombies, as soon you attack and kill one look out for more, they come in squads.
~ Baby, No tips really, I just try to kill as fast as possible.
- Creeper, Hit and run to kill, you have to rely on seeing them than hearing them since they are silent. SSssss
- Skeleton Archer, Use a shield against Skellys. As soon as you see the white tip off the arrow being drawn from their bow BLOCK,
- Endermen, don't look at them, avoid fights with them
- Spiders, No tips

I have a really hard time understanding how one can die from PVE in god armor to be fair, but moving on...
Listing stuff from the top of my head here...

1) Always wear god armor + an elytra, and have a god chestplate in your inventory, or vice versa, though I recommend having your elytra equipped as it's a much faster and safer way to get away.
2) Always use god tools and weapons.
3) Always carry a bucket of water and a stack of ender pearls
4) Always make sure your hunger is completely full. If it isn't you will not heal, making you much more vulnerable during combat. (Use high saturation food, btw. Steak or golden carrots.)
5) Always carry at least a stack of scaffolding blocks.
6) Always have a shield equipped. This shit is OP as hell.
7) Always have shit that can save your butt (such as ender pearls, water buckets, fireworks rockets) in your hotbar.
8) Know your limits. If you think you will die, do not proceed. Get to safety ASAP, and rationally think about the situation and your options.

And in case you DO die, because you will. Humans aren't perfect.
1) Have backup sets of your ENTIRE INVENTORY and use this to get your gear back when you die.
2) Always have your coordinates up when there is even a slight chance you might die so that you can get your gear back.

And lastly... get good. Absolutely no spite intended here. Minecraft is far from a competitive or even self-competitive game, but situational awareness, quick thinking, aim, reflexes, strategy, and basically anything that makes a person good at video game (or anything for that matter) can be trained.

What exactly is "God armor" ?

I never knew you could put Thorns on something other than a chestplate. As for the sword, Sweeping Edge would be also be a great investment that the chart had missed.

My advice to you is to get good at surviving with cheap gear, and then gear up. Don't spend all your time getting god sets, losing them, and getting more. I suggest to get a basic iron or diamond set with a decent pickaxe. Just go mining, and work on staying alive. And then when you have a decent amount of diamonds you can spare, and work up skill surviving with cheaper gear, then upgrade. :-p. You'll be less likely to lose it then XD.