How to prepare for transfer admission?

I just started college a few weeks ago and though I am liking it, I find that my school is not a very good fit socially or academically. I enjoy my classes and profs, but would like to see if I can get into a school I would feel more satisfied next year.
Anyway, what are the essentials to applying as a transfer beyond the requirements given by each schools? I know there are many threads with this same question but I would like to ask some specific questions I couldn’t find.

The schools I am thinking of applying are Brown, Northwestern, Dartmouth, Cornell, Tufts, Swarthmore, Penn and maybe Wesleyan. I might apply to more schools, but I’m not sure. I know they’re super difficult to get into; that’s why I want to start preparing already (beyond getting good grades in college).

How important are high school grades? Specifically for the schools I mentioned and the like.
Mine are not SO bad, I have a 3.6 GPA (bad freshman year and in my senior year I have 2 B+s, but sophomore and junior straight A+s and many APs/honors). Also, I dropped/withdrew from my French class on my Senior Year because honestly I did not find it very interesting. It appears as a W on my transcript. How can I make up for this? Maybe taking another language I’m more interested in next semester in college? Or is the damage irreparable? lol

Second, the SAT. Most of the schools I will be applying to require it from all transfer students. I didn’t do great the only time I took it last year, so I will take it again this fall/winter. Is it a huge factor? Do I need a score comparable to - or even higher than - the scores for entering freshman? How would you advise me to prepare: an online class, a tutor, by myself, etc.?

Extracurriculars. This is perhaps what is most unclear to me. Most schools say that they consider this for transfers but it is a secondary factor (implying, maybe, that they are not as important for transfers as for freshman applicants). So how should I pick my extracurriculars? What type of extracurriculars should I get involved in - are most applicants to those types of schools involved in super impressive extracurriculars, winning prizes and accolades?

Can you think of any other factors that I should consider that I didn’t mention?

I’m an international student, if it matters. I couldn’t visit all of the schools I applied to, including the one I’m attending, so that might be a reason this school isn’t what I expected. Now I will have that chance to visit many schools before applying so I can make a better decision if I transfer.

P.S. I am giving my best in my current school and I am getting involved and enjoying my experience here. So it’s not like I am reluctant to having a good time - it’s just that I find myself unsatisfied when it comes to some factors I was really looking forward to in the “college experience.” I can only go to college once, so I might as well just try to get into those I find are more suited to my needs and interests. If transfer doesn’t work, I will still try to get the most out of the college I’m attending. I’m just clarifying this so no one starts questioning me for thinking about transferring so soon.

These all seem out of reach to me given the information you have provided. Transferring is harder statistically than regular admissions at all of them, and it doesn’t sound like you would have had any chance as a freshman admit. Also, do you need financial aid? That would reduce your chances further.

You are transferring only for prestige. The few transfers who are admitted to these schools need a valid academic reason to transfer.

@TomSrOfBoston Hm. Not really. For example, Brown talks about students who are unhappy at their current schools and taking the initiative to apply to Brown as admirable. Big classes and their scarcity are my main reasons for transferring. It’s just not satisfying to be taking classes you don’t really want to take because the ones that interest you are full, and once you’re in the class, there is little interaction or time for discussion.

Few - if any - of the schools I mentioned require students to give a “valid academic reason for transferring” if what you mean by that is lack of desired major, specialization, program, or something like that.

Whether I transfer for prestige or not is not my question or your business.

You weren’t a feasible candidate for any of those schools the first time around. You apparently didn’t do your homework well enough to understand what type of college you were enrolling in this year. There is really no evidence that you are capable of that higher level work now given your grades & test scores in high school. Regardless of your reason for transferring, your odds are not good.