What should I cut out from my SOP for master's programs?
This is impossible to answer without seeing your SOP (which you should not post here). I'll give some general advice about what's important and not in an SOP.
Your mileage may vary of course, but on average, SOPs are very poorly edited. For the average student in your position, they could keep all the content and save 30% just by eliminating unnecessary detail. Common offenders:

Stuff that's in the CV.
Pointless stories about their childhood
Lectures about their love of their chosen (sub)-field, or pontifications about how important the subfield is
Complicated verbiage (a good editor can really help you here, but can be hard to find).
Technical detail -- choose one or two specific challenges you had and how you overcame them, don't describe everything you've ever done
Therapy sessions about a traumatic experience they had (unfair professor, etc.) -- SOPs are not the place for this

To your paragraphs:

My interest + view on the subject + long-term goal

Your first paragraph should be an attention getter (bonus points if it's humorous). Make sure you aren't pretentious about your &quot;view on the subject.&quot; You should state your research interests -- what you've researched and what you want to do next. If your long-term goal is to be a professor, omit this (everyone would like to be a professor in the same way that every basketball player would like to be in the NBA).

Background from college 1
Background from college 2 (I've transferred from 1 to 2)

Good, focus on challenges, in particular program-relevant challenges (lab work, most difficult/enjoyable class, etc.)

Skills and other important points about my background

Skills should be in your resume. &quot;Important points about my background&quot; sounds a little suspicious, but of course I do not know what you plan to say. If you keep this section, it should be about any major accomplishments during college that do not fit elsewhere (teaching, sports, career, etc.).

Research experience 1
Research Experience 2 (I've briefly described the project too.. is it necessary to do that for Master's programs?! )

The project should be on your CV. Here you should describe what you did, what you learned, challenges/highlights of the project, and how it affects your career trajectory (e.g., interest in doing more, wanting to do something else).

Short-term plans

I assume your short-term plan is to go to the master's program, not sure what you plan to say here. Consider omitting this unless there's something really interesting.

Why this particular master's program

Yes.