You start at the reputation with (25) and with each next level, it's harder to reach the next one.There is no real limit on the maximum or minimum on your reputation.

You have to work really hard to achieve your reputation goal.

The Reputation Score is basically the way the Steemit community measure the value you have brought to the community.The number in brackets beside your username is the most visible measure of the value of your account.

The number of followers you have and the number of people you follow does not have a direct effect on your reputation.
Important thing is ( I find out after year here) that your reputation score rise only from upvotes of higher ranked users and they help you get to the next level! Regardless of how much Steem Power you have in your wallet, that won’t make any difference to your reputation score. (correct me if I am wrong)
I am not a expert on this topic but I am good in making videos(at least I think so;) so I made another one:)

I made a video that illustrate building of Steemit reputation from the sketch- hope you like it.

If we have a good reputation score that will increase our chances to catch the eyes of other good power users.
So my advice to all new users is - provide a good content, be open to discussions, do comment and do reply, but be aware that everything you do, write and say here it stay here forever - so do your best not a spam!
Good luck!