As someone new to the game, should I start off playing with fewer players or should i play with the maximum setting ? Which will help me play better ?
Having played 2 games ( 5 players, 10 players ), I feel they're very different.

Yes they are completely different. I find that most players think the happy medium is 8 players. In an 8 player game there's usually only 1-2 players who don't border you but as the game progresses you eventually get a border with them making it more dynamic I find. In 8 player games it is also easier to find an alliance with someone. Smaller games are WAY more dependent on alliances. So it depends how much management/trust you like to put into a game. Small games require a TON of trust in your allies and hoping they don't backstab you and turn the tables whereas a 10 player game requires almost no trust in an ally because chances are they will be attacking someone else if you're friendly with them.

(I find that even though the trust factor is lower, 10 player games are more chaotic)

It's really up to you but 8-7 players is a happy medium

I agree with riot. I've found me the best way of learning is just experience. Play. But play one game at a time (or at overlapping ends) so you can focus. Watching videos is a good way of learning to think outside the box.

You should try to play 8-10 player games in my opinion. The first 5 games I had played were 8, 9, 10, 10, 10. I learnt a lot from these because they were much more dynamic and less dependent on diplomacy (which is good imo). They also last longer and more people = more interactions between players = more chance to learn more things. In fact, the number of handshakes 5 people can have with each other is 3 and a half times less then the number of handshakes 10 people can have with each other (without repeating any pair of people of course) Find the highest rated player in there and try and watch what he does.
You can also find lots of materials if you search up 'guide' or other guide-ish keywords in the 'general' forums.