How to prepare HR answers for Summer Internship?

While it can't be denied that one can never prepare an exhaustive list of HR questions that get asked in an interview, one can most definitely prepare to answer to answer all such questions by following this four-fold strategy:
(a) Preparing for the Obvious questions:
Obvious questions are the ones that are most likely to be asked in an interview. These questions are the only set of questions that you will actually prepare a written answer for. For all the other questions, you will follow a separate strategy (discussed in point c). Obvious questions include questions like:
-Tell me something about yourself
-Strengths and Weaknesses
-Long and Short term goals
-Why this domain? (Why Marketing?)
-Why this sector? (Why FMCG/Telecom?)
-Why this company? (Why HUL?)
-Which role would you prefer?
-Favorite Brand/Campaign/Ad
Remember: Apropos your CV, some more obvious questions might get added to the list, for example: Why marketing after 2 years of core operations experience? And the like.
These questions set the tone of the interview.
(b) CV prep: Your CV is your spokesperson. More often than not many behavioral questions spring from the CV. To prepare your CV, number every point. Every here means EVERY. Something as trivial as your hometown written in the educational qualifications column should also be numbered. Elaborate each of these points in a notebook. The interviewer, more often than not, gets intrigued by one particular point and keeps questioning about it. Building depth about points is therefore integral. So while doing this activity you will briefly revise every minor detail about things that you have mentioned on your CV.
(c) Repository of events: By now we understand that behavioral questions are innumerable. One cannot prepare answers specific to every question. What we can do is, make a "me map" (I will send a sample) and elaborate say 5-6 major instances in our life, dissect it completely. The selection of these events should be such that you cover both good and bad events/experiences. Also pick events from different walks of your life: work, undergrad, clubs, academic life, among others. Once you have prepared these events at length, all your HR answers will spring from their Repository of Events. So at all points, you know what to talk about and how to Structure it. You might not have prepared for the question asked in particular, but you have the answer in your Repository, irrespective.
(d) Top 5 best points: Always have a short checklist of Top 5 most important things about you ready. These points are your USP. You have to bring these points into discussion somehow. These points will help you drive the interview.

Good Luck!. 

A summer internship interview is less about subject matter expertise and more about you as a person. An organization wants to know whether you are a culture fit for that company, based on certain behaviors and mindsets that you exhibit. Remember, this is an opportunity to market yourself. Until and unless you steer the dialogue in the course of this interview, you will not be able to control the outcome. 
First and foremost, know your life story inside out. This is much easier said than done, but this is where all the hidden obstacles lie. You should be able to answer why you did xyz point on your CV. Once you've answered why, you should be able to defend that answer with another why. Dig 3 whys deep into each and every point of your CV. Spend time on this exercise, because this will exhibit a number of important competencies such as clarity of thought, ambition, drive, goal-orientation. You want the recruiter to know that everything that happened to you happened because you had some agency in it. Don't come across as embarrassed if you are asked about low marks/gap years. Own it proudly and show how this was a choice, where you prioritized maybe a personal goal over academics or paint it as a learning, demonstrating how you went onto do much better once you failed at something once. Most importantly, link your life story to your future aspirations. Everyone wants a candidate who is consistent. So show them how something you did a year back (maybe an online course you took) was done keeping in mind what you have in store for yourself 5 years down the line. Your story should be a logical flow between past, present and future. Doesn't mean it has to say the same things through out. Changing career tracks is natural-you are evolving! But this needs to come through clearly in your responses. Honestly, if you spend enough time thinking about your own life story, you won't need to remember rote answers about long term and short term plans: they will flow naturally because you have convinced yourself that the story YOU are projecting is the one that truly is!
Lastly, remember that it's not so tough: you have just got to make the panel like you! So use all your artillery: a cute smile, a little well-timed humour, do all the things you know you can do that woo people over. 
 
 

The thing about people is that we all have a unique set of values and principles we abide by. We all have a unique mix of competencies. For the sake of summers, your Behavioural questions need to be well prepared. You should be ready with instances from your life so far that shed light on problem solving, conflict resolution, creativity, value system etc etc. The companies are looking for a match. They will hire you if your value system matches theirs.
Have a clear statement of purpose. Know your CV in and out. Have 'hooks' in your answers. Mention unique events/incidents that intrigue the interviewer and open up the possibility of discussions. Make sure the examples you give from your life are unique enough. Everyone has generic answers ready and the panel has heard it all. Having a differentiating story/element would go a long way in your favour.
Also, remember everything in your CV. Do not come across as someone who 'doesn't remember'. If you have written it, you should know all of it - the points that are on your CV and the points that are not on it.