Just starting Fallout: New Vegas

This guide should answer your questions

http://www.ps3trophies.org/forum/fallout-new-vegas/74050-fallout-new-vegas-trophy-guide-road-map.html

Everything aside from the story trophies are missable because no matter your ending, you leave New Vegas. Put your points into lockpick or science, repair, and your preferred weapons. Make regular trips to shops if you only intend on doing story in one of your playthroughs, so you're not doing the last mission with eight stimpaks and 9mm bullets lol  In regards to glitchiness, almost everything except some minor glitches and freezing have been patched, so nothing to worry about. And the most important rule of al l: Save often. Make 2 saves, not just 1, or you'll be helplessly stuck in a rock, with no option but to start over, like me

Na your companion damage doesnt count for the trophie. I got the trophies by stacking up on a weapon type, saving on the strip, switching to very easy, and just kill everything.

I would've done hardcore first… It's a pain… Not hard, just a bit of a pain…

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If you don't want 3-4 full runs alternate main story quests between the four factions as much as you can before you effectively 'cut-off' the other three factions, then use that as a 'base-save' to replay the other endings… You'll still need to play chunks of it again though… Some trophies are faction related…

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For the 10k+ weapon trophies… For my second game i built an Char. spreading the skill points to things needed for each of the trophies pretty evenly till about Lvl17-19, but 200-300xp before you lvl. up to whatever you chose, save, get a decent/special weapon needed for trophy 'X', then get killing at the strip… When you Lvl. up at the strip you can put all 13-15 skill points into the skill you'll be immediately using giving you a hefty boost to stats… Reload, rinse, repeat for each 

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The food trophies can be done by buying all the food from the dude in the halls of Camp MCcarren(?), wait three days, but it all again, repeat untill you have loads then get to some water… Drown and munch all your food… (Thanks to whoever told me that from the site… Can't remember who, but this wasn't my find )

For stimpaks… The medical centre beside Crimson caravans has 7-12 stimpaks every 2-3 days… Drown, heal…

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Another speed-run with a Char. built for massive luck for 'The courier who broke the bank'… Depends if you can be bothered playing it for ages legit?? And Caravan is rock solid after the patch, so perhaps even another quick run (-patch) for those two quick??

I got the two Caravan trophies before the patch but I've not played much at any Casino to know if it would take long? But I think it's like $5000, $7000, $12500 (or there equivalent in caps) to bust the three main Casinos

Everything else is pretty much straight forward, although I've not found many terminals for hacking, so be vigilant!!

RKF95 said:

Theres 4 branching endings, just save right after you get the chip back at the tops casino, so that you can just reload that save after you complete one of the endings.

RKF is right; it's not that you need seperate playthroughs you just need to get the different endings. Do what RKF95 suggested bc that's what I did. Hardcore is not really hard bc there is plenty of food and if you need water just fast travel to the Goodsprings Source it has a water, food and sleeping place so you can rest up. It also has geckos you can kill and then cook there meat into steaks. In my opinion, hardcore mode was just a nusance and everyone was just making it seem like it was impossible.