Three interview round.
1st- HR
2nd- Aptitude
3rd- Team Lead
The HR round with EY is to be taken seriously. It is the major sorter to minimize candidates. Prepare well, so that if a question arises out your expected ones/comfort zone, you have things in your mind and can answer on your feet.
The HR person was very intelligent, discerning and frank. I admire their professionalism. Remember, it is Your duty to convince them that you are for this. Be rational and smart with your responses, with a tidbit of emotion.
The Aptitude test should be taken seriously, in the sense that you must clear well above their minimum standards, BUT my instinct told me the HR person had already taken calls on the candidates she wanted to pursue with and what profile they would be most beneficial for. Aptitude is just a basic step, so clear it nicely too. You don't want to fail there after impressing the HR.
The Team Lead who you'd be working with takes the final round. It's a consolidation round of sorts, where the questions might be similar in the beginning. Since you've already gone through the HR process, you already have live practice. Don't lighten up now. Answer even the similar questions with the same amount of enthusiasm, rationale and professionalism. They're also human beings, so they're also curious about who this person is who's going to be working with us. This round got technical post the general questions. A situation was given, and I was told to assess the kind of risks that could be associated with said situation. I explained why & how something could be a risk. The interviewer has my respect, because he gave me another perspective in between, told me to look at the problem from a worm' eye view too, and answer accordingly.
Very positive process. Your logical and analytical ability, along with your reasons to back them up ill take you through. Enjoy the process, be generally logical in your approach.
Wonderful vibes and working environment.