I'm only on my second character.

I learned to get Intelligence to 9 before leaving Vault 101.

Explosives should be at 30.

Don't disarm the bomb before you have a chance to kill the creep who wants you to detonate it--and take his gear (???)

And that's about all I think I know.

I'm wondering if I should put every effort into getting Lockpick and Science to 100 as fast as possible, since I've run into doors and computers I can't get past fairly early in the game.

Or, should I be more focused on Small Guns and Repair? Or all four?

Basically, when starting a new character, what should you keep in mind, so it doesn't come back to bite you later on?

Oh, and does the game have a hardcoe setting, or is Very Hard the max?

Thanks for any help!!!!!!!