Since you already have a valid US visa suitable for your purpose of entry, you should be admitted without difficulty. You should have your address in the United States to hand, and the contact details of your friend. It might be useful to bring a bank statement to prove your ability to fund yourself, and to prove that you have steady employment in India and you are not seeking work in the United States.
The pre-clearance station at Abu Dhabi (and indeed anywhere else) is almost exactly the same as clearing US Customs and Immigration on US soil. The US CBP officers there will process your application to enter in the same way as normal. They can deal with complex cases including new immigrants and ATA carnets. The main difference is that the officers there have very limited powers to detain you against your will, and you may withdraw your application to enter at any time and leave the pre-clearance station.