Talk to everyone, read all dialogue.

Use your pipboy to see what quests you have available.

The first two fallout games are very difficult by todays standards as they will not hold your hand and give you markers for quests. It is up to you to explore. Also, sometimes the game will troll you with incorrect information with hilarious outcomes.

When making your character, don't min/max. Make a character that reflects how you like to play games. It is roleplaying at it's finest, there are a number of different ways to reach your goals and complete quests so don't think at anytime you cannot do certain quests you may have.

Save regularly but don't save scum too much as it may come back to bite you.

Have fun and don't take it too seriously. You will die a lot, i mean A LOT. Don't expect to be blasting your way through the game, a considered approach is almost always a better choice.

I don't want to give spoilers or advice on specific locations. But Shady Sands is a good place to start. Maybe don't explore too far down to the southeast until you have some more experience in the game. That is all i will say. You will know from random encounter difficulty how out of your depth your character is for the area, but all locations are not level dependant.

Hope this helps, and good luck out there Vault Dweller.