The Common Application is improving every year and one of the best ways to learn about it is to set up a dummy account and explore - have a go here: https://www.commonapp.org/. They have recently launched Commonapp ready :http://www.commonapp.org/ready, which talks you through the process.

Alternatively, if you are the kind of person who would prefer to follow step by step instructions, below is a downloadable guide from the Fulbright Commission that is a tiny bit out of date, but still relevant. 

There are two kinds of recommendation provided for students for US applications:

1. The Counselor Recommendation
​2. Teacher Recommendations

The counselor recommendation
The counselor recommendation is significantly more important than teacher recommendations as it brings the whole application together and contains a number of elements. It is constructed as follows:

• May, Year 12 - Subject teachers are asked to write positively and specifically about the student's attributes in their subject
• June, Year 12 - Tutors gather together these comments and add information about the student's extra curricular activities, personality and any anecdotal information they have.
• September - December Year 13 (depending on student's chosen time of application) - Counselor develops the recommendation further based on conversations with the student in order to create an over arching theme, to best reflect the character of the student and to make the recommendation engaging, readable and above all personal.                                                                           

Teacher recommendations
Universities will ask for additional recommendations from two, sometimes three teachers. In addition to teachers at Dubai College, students could also consider coaches or music teachers who they have a relationship with outside school. The criteria most cited for these recommendations are that the writers should:

• Know the student well and like them!
• Write specifically and anecdotally
• Be honest about areas for growth / improvement
• Try to highlight the student's potential at University level
• Be from different disciplines - i.e. it is good to have a humanities/arts teacher write one recommendation and a science/maths teacher write another 

It is important to remember that, valuable as these teacher recommendations are, they always show the student in a positive light, which can devalue them in the eyes of admissions representatives - making them possibly the least important part of the application.

SAT
Online practise and training:
http://www.cracksat.net/
https://www.khanacademy.org/
https://collegereadiness.collegeboard.org/sat/practice/full-length-practice-tests

The resources below cover the two key types of college essay:

1. The Commonapp essay - the prompts for which remain broadly similar year on year
2. The Why This Institution essay 

I will add more resources here as I get them / make them, but I think it is important to remind you that essays must be personal and no exemplar should be taken as a guide of what is right or wrong. The best resources available to you are http://www.collegeessayguy.com, and myself - I've been reading, reviewing and advising on essays for a few years now - I know how they work and I have a good ear for quality prose - there is no substitute for you and I sitting down and chatting about who you are, what motivates you, and how we best convey that in writing.