LinkedIn grown in popularity over the last five years and pretty much everyone in banking and finance is now on it. That makes it an excellent platform to reach out to people you otherwise wouldn’t have access to.If you are looking to secure an internship for the summer, or even a graduate job, then cold messaging people on LinkedIn would be another approach, next to filling out tons of online applications. Before you go any further though, there are clear do's and don'ts when it comes to cold messaging senior professionals in banking. Here it goes.Do Not:Ask silly questions like 'what advice could you give me to get into banking?’Seen this so many times, and everyone sees through it. When you message someone in banking with questions like what advice could they give you to become a trader or even worse, “what does your job entail from day to day as I am looking to move into that field”. It is very obvious. So if you are messaging because you want something, a job or an internship, don’t sugar coat it as it’s not necessary. People in banking are very direct so you should be too. Make it clear why you are messaging straight away.Write to someone with no decision making powerMake sure you are writing to the correct person, aka someone with decision-making power. If you message someone junior they might feel threaten by you, if your CV is strong, and delete it straight away. So make sure your message goes to someone at the Director or Managing Director level. Ideally you want to message the desk head.Write your life storyNo one likes reading long messages. Keep them short and precise. Otherwise, in most cases, they won’t be read at all.Do:Make sure your LinkedIn profile is complete and professionalThis is a no-brainer. Surprisingly, however, I have seen quite a few half-arsed LinkedIn profiles from people who have messaged me to ask for internship vacancies. Make sure you have a professional looking photo, i.e. a headshot of you in a shirt and blazer with white background. You don’t have to pay for a professional photo shoot. A headshot taken with your smartphone does the job. Highlight your education, professional experience and any that makes you stand out from other candidates such as a sporting achievement, an exotic language or notable charitable activities.Contact Tier 2-3 houses to inquire for internship opportunities, and just askBig investment banks and asset managers have large graduate recruitment procedures and processes. Therefore, trying to get a job or an internship at places like Goldman or JP through messaging a Managing Director on LinkedIn is not going to happen. However, at the smaller houses which don’t have large HR teams in London and so no official graduate program, those are the ones you want to contact. At these houses you could also message someone in their HR department, though reaching out to hiring managers is always the better option.Good examples would be banks from Asia, the Middle East and Australia who tend to have smaller branches in London and therefore generally have no structured graduate recruitment process for their London offices.Optional: Publish on your LinkedIn profile (that hiring managers of potential employers may read)LinkedIn has introduced a new feature that allows you to publish blog posts on your profile that you can make publicly available. I suggest you write one or two industry relevant posts sharing your opinion on a certain subject matter. It can signal that you are interested, articulate and are able to communicate your ideas and opinion. Those are qualities managers look for in new talent.By now you must be wondering ‘but does it actually work?'.The answer is yes! It does work.I have seen it happen several times but don’t expect to receive a lot of replies. Like internship and job applications, it is very much a numbers game, but I have seen several people ‘get lucky’ and get internships off the back of cold messaging someone on LinkedIn.Once you have completed all the official online applications for the large financial institutions try to reach out to people directly at the smaller houses. You’d be surprised by the results.Remember, fortune favours the bold!