How to figure out what's going to be on an interview?

This depends what roles you are applying for. Are you looking at Software Engineer, Product Managers, or other roles? What kinds of companies are you applying to? You can generally find mock questions on Glassdoor for larger companies. For software roles, Leetcode (data structures & algorithms) tends to be the gold standard. When looking for the answer to this question for you, you'll want to look online or ask here based on what you are applying for.

As far as the behavioral questions, there are some themes, but it will vary by interviewer. Some companies have specific requirements, like Amazon focusing on their Leadership Principles, which you want your stories to relate to. Preparing detailed, clear stories for different themes is important. You can look up formats like the STAR method.

Once you have interviews lined up for specific roles at specific companies, you can make your preparation more specific. Until then, think about the roles you want to apply to and cater your interview preparation to generally getting ready for those roles.

This is a high-level question, but it's a good one as I've seen so many engineers mess this up. Of course, there are always going to be curve balls on interviews, but there is a surprisingly high amount of information you can extract to focus your studying and boost your chances.

I have a lot of thoughts here, so I'll split my interview scouting tactics up into 3 sections:

1. For All Interviews
2. Big Tech
3. Startups

For All Interviews

1. Ask the recruiter - Seriously, just ask them. If a recruiter has decided to give you an interview, it means that it's now in their best interest to maximize your chances of passing. This is because they have now invested time into you, and by not throwing your resume in the trash, they are implicitly saying "I believe that this person won't completely implode in our interview process". It doesn't make sense for the recruiter to give you the thumbs up to have you walk blindly into a trap where every question is some random, unexpected "gotcha". You can simply ask something like: "I want to make sure I show my best self during the interview to ensure that your time interviewing me is well-spent. Can you give me some pointers on what kinds of questions and challenges I should expect so I can better prepare?" If they don't respond, that sucks, but you have to at least try. A lot of engineers are awkward and afraid that the interview will be rescinded or something if they do this, but there really is 0 downside if you ask it politely as I mentioned before.
2. Go through your network - This one's obvious: Ask people you know to see if they have gone through the interview or know someone who has. This is the highest-grade information and one of the reasons why having deep work connections is so important (and again, this is something many engineers are bad at because they're shy and awkward). If your network isn't strong enough for this, follow the advice here: [Masterclass] How To Build Deep Relationships Quickly In Tech
3. Research what they do - This is another basic one, and it's especially true for startups (but it works for Big Tech as well). If a company uses ABC tech stack to build product XYZ, there is a great chance their questions will center around those, especially in the system design round. If you know who your interviewers will be, look them up on LinkedIn. In fact, I know an engineer who interviewed with LinkedIn and realized that the engineer doing their system design round worked on LinkedIn feed. Now guess what their system design question was: It was to build the LinkedIn feed!

Big Tech

Big Tech interviews are tough due to the difficult questions and strict grading, but this is heavily counter-balanced out by their predictability. Here are the 2 things you absolutely have to do for every Big Tech interview:

1. Go through their Glassdoor - Read through the past 3 months of data at least, if not 6. Write down and master every question you see 2+ times. The more a question shows up, the more you should prioritize learning it. When I studied for Meta, I made sure I could do literally every question I saw across Glassdoor data, and I used a giant Google Doc to keep track of it all.
2. Master their Top 50 LeetCode problems - Question frequency is the killer feature of LeetCode Premium: That alone is easily worth the $35/month. To me, Top 50 is the baseline, but if you don't have the time, do the Top 25 at least. Back when I interviewed for Meta in 2017, LeetCode was a lot smaller, so there were only ~110 questions tagged to Meta: I did every single one. Again, start at the top (i.e. most frequent) and work your way down - It's just like Glassdoor.

If you are completely blindsided by your Big Tech interview, you probably did something wrong.

I talk about all this more in-depth here: [Masterclass] How To Ace Your Big Tech Interview - Data Structures And Algorithms

If you're interested in my Meta story: How Alex Got Into Meta With 0 Prior LeetCode Experience

Startups

Startups are much trickier, especially if they're on the smaller side (i.e. Series B or earlier). At a high-level, startups will generally rely more on practical coding, but this will vary as the startup ecosystem is inherently high-variance. I cover startup interview tactics in-depth here: "How to prep for interviews at a startup?"

Congratulations almost graduate!

Personally, I have not encountered a time thus far where the recruiter (startups and big tech) straight up refused to provide me any information on the interview process and pointers. (There has been one instance where the recruiter said they had no idea... probably not a great sign? Haha.) Typically, they have taken the time to brief me on the subsequent interview rounds and during that time, I have always received a helpful response to, "Would you be able to give me an idea of what the technical interview might entail? For example, is it sort of a real-life business-related coding exercise or a Leetcode type of problem?"

100% agree on what Alex and David have said~ scour Glassdoor interview reviews (a lot of info on startups too these days, as long as they aren't Seed stage) and be well-prepared for the behavioral round (using STAR method).