The answer to this question has to be a multi-faceted one. It is one thing to try to sell oneself, based on whatever skills one possesses. It is quite another to first acquire a wide variety of skills and then apply for better positions. It should be noted that there are several companies that look for candidates with the required skill-sets and are willing to pay very high salaries to hire such candidates from the market.
However, if you are a fresher, you are likely to be tested purely for your knowledge and your adaptability to the particular organizational culture. Hence, to be prepared for a good answer, you need to first acquire a great deal of knowledge about several aspects of the organization, with specific reference to:-
a) What industry domain the organization operates in and what are the Government regulations, the futuristic market scenario, the present position of the organization including profits or losses, the Management, and its intent, the Vision of the organization, the products, and services the organization that you are applying for provides and so on. This will enable you to answer any question related to your answer.
This needs a lot of explanation. For example, assume that you are interviewed for a sales position in Asian Paints. You are an MBA from a fairly good branded B-School. After your various tests are over, you might have the vital HR interview to contend with or you have the final interview straightaway. Asian Paints is a market leader and has many strategies up its sleeve to maintain its market position. Hence, you need to know everything about its market strategies and some insight can be from the dealers. If you chance to meet someone from the organization, you must approach that person as a customer to understand something about each of the variables mentioned above. Let us say, you answer "Sir, I have heard a lot about your campaign called "Lamination for the entire house". You are getting into a territory where you are bound to be asked several questions. Your homework will have to be to visit any house anywhere and check for the finest details about the cost, labor cost, how many days it took to get the task completed, the complexities involved, co-opting of the customer competence ( which means that the customer might also have offered them innovative ideas in one way or the other) and so on. Answers to each of these questions are never easy to come to buy. You should be brutally honest and limit your answer to anything that you know very well. Once you are done with whatever knowledge you know, you can add "Sir, I shall positively contribute in being part of the process of execution of such residential tasks and shall deem it a great privilege to add value" Remember, you are adding considerable value to your answer and are showing signs of getting totally involved. This is exactly what is called for.
2. Now, let us come to the next possibility. You have five years of experience with a competitor. You were in field sales and had an experience that gave you great insight into customer expectations, the challenges involved in the rural areas, and whatever knowledge you had acquired in the process. You have to be brutally frank about what you know and not bluff or beat around the bush. No employer likes someone who tries to hoodwink the interviewers. This will not fetch you the job at all. People are looking for cultural adjustment and additional disposition to a very large extent in lateral recruits. You should hence note to be very careful to not give any information that will sound harsh or meaningless. You also need to be very careful to project a picture of optimism. Once you do so, you have already answered the question, "why should I hire you".
3. Note the changing skill-sets, that are now becoming common across industries. For example, it is essential that you know the basics of SAP in Finance or Materials Management, or even Marketing. It is also essential that you have at least a certificate course in Six Sigma and Machine Learning. If you can acquire a Diploma in Artificial Learning, even through online mode, remember, you are on the right path and you will be rewarded for your expertise, as the questions will largely revolve around how you can use these skill-sets. Multi-skilling is the name of the game.
4. Let us take the field of HR. If you are stuck with say, one field, like the Administration of Training Programs, immediately quit the organization, and go to an organization where you will have tremendous value-addition. The world of manufacturing is in for a massive revival for a big demand for skill-sets that center around managing armies of contract labor. You need to cut your teeth in such environments and acquire vital experience. If you have factory experience, you can easily move to the IT industry, where you will have enough exposure to psychometric tests, 360-degree appraisal, mentoring, and so on. These skill-sets will make you an all-rounder in around seven years and you can feel very confident that you can easily answer the question "Why should I hire you?".
4. Please do note that the question can indeed take various shapes. In the process of assessing the quality of all your experiences, you are likely to be answering questions related to the depth of your knowledge. For example, if you had documented the experience of handling local trade union leaders, in the process of educating them to agree to the Management point of view during the preparation for the statutory wage settlement, you will be in a better position to present different perspectives of employee expectations, the Management stand on various issues and so on. For example, if there had been a provision to control absenteeism that was agreed in the final settlement, the process of getting the trade unions at the local unit level and the Corporate trade union leader to agree to that as well, would have been the greatest of learning experiences. If you had sound knowledge, you will automatically graduate to a stage where you will be hired for a better position. If the organization is a multi-unit, multi-product enterprise, you can rest assured that you are on a sound wicket to acquire the best of experience.
All the very best in preparing for an answer. Just understand the contextual variables as explained above and prepare for the hard grind. Thre is no free lunch anymore and you need to understand this as a way of life.