In my IELTS test, should I focus on Task 2 and not worry so much about Task 1?
You need to do well in both Tasks to score high (7.0 and above).
You need to be a 'master' at both Tasks with minimal errors in both to achieve 7.0 and above.
Focus on both Task 1 & Task 2. If you are worried about Task 1, spend enormous amounts of time reviewing sample answers from native English teachers.
Remember this point: Task 1 is the first Task the examiner will mark. If the examiner encounters a poorly constructed, grammatically-weak answer, it can influence him/her negatively when it comes to marking Task 2!
It is a mistake to focus all your energy on Task 2 to the neglect of Task 1. You must have all the elements of a good answer: an introduction, suitable comparisons, a summary/overview statement.
Make sure you read a variety of model answers and aim to copy the style, organisation, vocabulary and grammar of what you read. You improve your writing by reading lots of perfect models!