Yes, don't try to get 400 subs by the end of February. That's just a selfish ambition. It's gotten quite old people asking about how to get more subs instead of how to provide greater value to a greater number of people. Instead think of how you might help more people. It's about them, not you.
@Andrew said it best
I am continually amazed that people want to know how to get more subscriber yet they haven't bothered to tell us basic information about what they're doing. In some--not all--but some cases they haven't even thought about teaching, helping or entertaining people. What's more some--but not all--don't even have a basic topic for their channel, yet they want more subscribers.
We here at the forums say the same think over and over and over.
This is not an attack but an observation on FAQ here on the forums: The basic questions never seem to change. It's usually--not all cases--but usually some form of "How do I get more views, subs for myself?" Until that question changes, until the paradigm changes to how to I help, teach, entertain people and make it worth their time, energy or money . . ." These kinds of questions are what set you in the correct mindset to build a YouTube channel.
It has been my experience that once people come up against this wall, they usually quit shortly after.
That doesn't mean you chase bunny rabbits down the hole. Instead think of the You in YouTube as You giving educational, instruction or entertainment value to people. It's about You giving, not You getting.