Step 1: Send in CV and cover letter - emphasize customer service, can-do attitude, any relevant sales experience or business/finance interest.
Step 2: If they like what they wee you'll get a phone interview. This is very easy and hard to fail. They want to see that you are "nice"/fun/pleasant (i.e. fit in with the work culture), that you have a basic understanding of the role you are going into (if research analyst this is researching different markets and identifying industry experts within these areas that we can put our clients in contact with), that you sound OK on the phone, and that you will not be too off-put from having to do some degree of sales. You will not find any competency based questions really. Perhaps one or two on why you think the role would suit you.
Step 3: Final stage is what they call "superday". It only takes two hours and consists of two interviews. In both they will want to learn more about you. Focus on showing a friendly attitude, curiosity and an inquisitive mind. Any examples of initiative and ownership will also be good. Prepare examples of when you have had to sell something, and about research. Talk to them about interest of different markets, and your analytical abilities. Definitely ask questions about the role and work culture.
One of the interviews will have a case study too. Do not be scared of this. It requires no prior preparation or knowledge of the market you will be discussing - just common sense. They might ask: "Our client is looking to buy a company that manufactures professional coffee machines, who might we want to put them in contact with?"
Start by outlining the value chain for them - who are the possible stakeholders? There are so many options here, but examples are e.g. suppliers of parts to make the coffee machines (is there perhaps someone who supplies the coffee filters, or does the manufacturer manufacture these themselves?), adjacent suppliers - people who provide the coffee beans might have thoughts on the market for coffee machines), obviously customers - who might buy the coffee machines: cafes (Costa, Starbucks etc), Hotels, Gas stations that provide coffee on the go, offices who provide coffee for their employees, conference centers, restaurants and so on. Finally you have competitors, if anyone will know the industry it is them.
End with telling them what type of person you need to speak with in each part of the value chain. Start by telling them what information they could help give insight into, and continue to explain what type of person (what title) within those companies would have insight into that:
Part Manufacturers - can provide insight into who buys from them and what they are looking for when they choose parts, if it is price sensitive etc. Therefore you would most likely want to speak with someone in a sales position.
Adjacent suppliers - Depends on what your basic assumption is. If you assume that bean providers will buy machines, you'll want to speak with someone in procurement as these are the ones picking the machines and know why they would pick a certain brand. If you assume the machine manufacturer will buy beans you will want to speak with someone within sales (at the bean supplier) as they will know who buys from them and why. If you assume none of this happens, chances still are that these people will be experts on coffee and will know what makes coffee and coffee machines good. They will know the market. In this case, aim for high level people like CEOs.
Customers - As in the above point, you will want to speak with buyers at companies using the coffee machines. These will be able to give insight into key selection criteria (what influences the buying decision), how buying decisions are made (is it made locally or centrally within the company, is it by tender or individual negotiation, are there switching costs?), and will obviously also know what players there are on the market and how they differentiate.
Competitors - Here you usually want high level, outward looking people who know all market aspects well. A CEO or perhaps Commercial Director if possible.
Don't worry about remembering all of this. They will help you through it. Just stay calm and think logically and you'll be fine. Note that out of everything, personality is most important, you won't get the job unless all your interviewers vote yes, so don't be shy (or rude).
Step 4: Get the job, and start applying for new jobs ASAP. You do not want to stay there for too long. Trust me. (If you do, imminent death of either boredom or bullying is upon you. You have been warned.)
Good luck!