Banerjee,
I did the following, in chronological order:
1. Read the first chapter from Arco
2. Read the first 6-8 issue essays from Arco.
3. Came up with a format for structure of my issue essay.
4. Read the first 2 argument essays from Arco.
5. Formed a mental roadmap of my argument essay.
6. Practised 2 issue essays and 2 argument essays under timed conditions.
7. Took 4 full length tests including AWA
8. Studied first 20 issue essays : took a position, came up with and noted down 2 or 3 reasons in support of my view and 1 against and finally read Arco's take on the issue.
This strategy worked well. If I had time, I would spend more time on studying issue topics rather than on writing practice.
Good luck.