As
Zombra mentioned earlier, there's a scarcity of experience relative to all the things you can invest experience in, so for those who have yet to jump in, here are some beginner tips on how to get the most out of the early-to-mid game content.
Hierarchy of what to spend experience on in the early game, going from most important to least:
1. Dialogue Skills (Rhetoric, Intimidation, Persuasion, Psychology)
2. Knowledge Skills (Deduction, Education)
3. Attributes (Physical, Social, Mental)
4. Exploration Skills (Security, Technology)
5. Disciplines
1. Dialogue skills are the bread and butter of this game. The more points you have invested in these the more confrontations you can win and the more information you can glean. Psychology in particular gets used quite often by Galeb and Leysha, but all four skills are used by all the playable characters.
2. Knowledge skills aren't necessary to win confrontations, but they're satisfying to have and provide you with additional experience at the end of the scene for successfully triggering them.
3. Attributes help boost your chance of success during a skill tie. It's useful, but if you fail the roll,
you can quit to main menu before finishing the dialogue and jump right back in. This will reset you to the beginning of the conversation and you can roll for success again. If you don't plan on 'cheating' the rolls, then rank Attributes over Knowledge skills.
4. Exploration skills are not very useful in the early game because there are alternative ways of unlocking locked objects or accessing password protected computers. Usually by finding the key/passcode through exploration. Later on there are several consumables that boost these skills as well.
5. Don't invest in Disciplines. At least not in the prologue. After the prologue, having Auspex 2 and Celerity 2 is recommended for additional content. I wouldn't bother with anything else. There are some scenes where the game gives you additional content for having certain Discipline powers, but in those same scenes you get Tremere concoction macguffins that allow you to temporarily get the required discipline power if you explore the level thoroughly or successfully complete confrontations. Last but not least, the experience cost reductions that you get from feeding on humans stacks. This means that the Discipline that costs 45xp to upgrade in the early game will cost a measly 5xp or even 0xp to upgrade later down the line.
The more content you access the more experience you get. The more dialogue skills you use successfully the stronger those dialogue skills become through the Talent system. It's encouraged to win as many Rhetoric, Intimidation, Persuasion, and Psychology checks as you can.