What are some examples of "quick wins" you should aim for in the first 90 days?

I think it takes a thorough understanding of a product and its users to achieve success. For that reason, I am not a big believer in “quick wins”. Take the time to learn before executing and think of “winning” as the result of iterative experimentation.

That said, the main thing you, as a new PM, bring to the table is a fresh perspective. That perspective is invaluable and could lead to great insights. We all tend to make assumptions about users’ behavior or their likelihood to convert or churn, but approaching these with a new set of eyes could lead to a different conclusion. You should feel empowered to ask questions and challenge prior hypotheses.

A good outcome of the first 90 days would be a strong understanding of the business and your team. This can be gained by setting up time to speak to key stakeholders, interviewing users, analyzing data and doing research. All of these efforts will provide a foundation upon which you would be able to build a strategy and execute, hopefully, with several great wins!

“Rushing to prove value” is one of the common pitfalls of starting in a new role. Having said that, you want to make steady and incremental progress in delivering value. See my response to the question "What's your best product management 30-60-90 day plan to make a big impact at a new company?" for the framework you can adopt for a 30-60-90 day ramp up plan. Here I’ll outline some quick wins you can aim for but I can’t stress enough on not coming across as ‘rushed’.

• Relationship building with your team. Get to know them better as individuals, take the lead on setting up that recurring team lunch or happy hour, take the lead on driving that team stand up.
• Owning an in-progress project and taking it over the finish line (driving a product launch, leading a SEV).
• Sharing your perspective on product/customer pain points and what we could do to get better.
• Unblocking teams where necessary on a day to day basis.
• Documenting product flows, platform architecture or other business critical information as you ramp up. Often times when I wanted to ramp up, the lack of proper documentation is why it takes time. You could fix that for future team members.

The first 90 days are for quick wins. This is to help establish and validate your reputation quickly. You are going to want to pick something realistic that you can accomplish in 90 days. You Should also consider the following criteria:

- Can it be measured? If the answer is yes, get that set up before you work on the initiative so you can show your impact. 

- Does it have the potential for high visibility? For example, if there is no consistant roadmap view and you pull it together, its something that will be applicable to the whole team and likely will be shared with internal groups like marketing, sales, etc. 

- Does it showcase your orher skill sets? Do you have a background in data analysis? You may want to pull a dashboard together the team needs but doesn't know how to create. Do you have a background in research? You can help facilitate some discovery sessions or put in place a customer outreach program, etc? 

Find a pain point and help make it better by either measuring the impact, making sure the opportunity is visible, or by leveraging your skill set to increase the quality of the output above what exists or other could do. 

It can be tempting when joining a new organization to find something small to ship but you should remember that shipping does not mean a "win", you want to drive a successful outcome. So instead of focusing on finding something to ship, focus on finding a way to improve an outcome. That might be making it easier for the sales team to know what just shipped, giving the support team visibility into the bugs that are being worked on by the team or some other process improvement that makes life better for your customers or your team.