How to start making a composer portfolio for College application

I am a drummer and have been into composing music for picture for the past 8months and I have developed a deep interest in theory and composition. I am currently persuing my BE in mechanical engineering and would want to take up a major in composition.

I have question on how to develop a portfolio that can be deemed "acceptable" by these college for the department of composition. 

I have been reading a lot of theory books. Basic theory books. Started the Fundamentals of composition by Arnold a few weeks ago. Having a hard time reading the example scores. 

Any advice would be gold right now. Thanks :) 

Good question. I never made a portfolio, but I can share my experience with my audition for the pre-study classical composition.

When I did an audition for the conservatorium, there were a few points about the works you submit. (Lay-out is a problem on my phone, sorry).

- Three original compositions, which differ in tempo, atmosphere and instruments.

- These three works need to be a representation of your current writing. This may not apply for a portfolio, since its goal here can be ti show the process of your developing composing skills.

- A short motivation why you want to study composition and what you want to do with it. Furthermore, you can describe your vision on composition.

Hopefully this is useful for you!

Not to be a downer, but like any sort of music major, you should know things going in. The portfolio requirements for your school may differ, and the style they're looking for might be different (i.e. Oberlin is very classical, while UW is very modern). You will not get in no matter how enthusiastic you are without a working knowledge of what they want you to know... unfortunately, these things aren't listed on college websites, so definitely ask around. 

So you're already in school for mechanical engineering?  Or you know where you want to go, and want to add a music major at the same time?  Then talk to your school's music faculty about what they are looking for.  They are real human beings and would probably be delighted to find out someone is motivated enough to ask the question and start seriously working towards producing a good portfolio.  Or if you are working toward applying to schools for engineering, there may be a limited number of schools that you are focusing on that also offer a major in composition, so you can use that information to narrow things down and then, again, just ask.  Don't worry that you will be giving away that you are a beginner by asking the question.  They will be able to tell that from your portfolio, and that's why you want to study music:  to learn.  But the fact that you are asking how best to prepare NOW, and planning on taking the time to really put together a good application will tell them what sort of student you will be if accepted.  (A hard-working student, a self-motivated student, a passionate student).  You don't want to take up too much of someone's time before you even apply, but sending a polite, succinct email asking where you should focus your efforts can only help you.