Everyone hates building their portfolio. It’s way too easy to descend into comparing your work to all your heroes, obsessing over unnecessary details and starting to doubt yourself. Don’t fall into that trap. Treat it like a strict brief with clear objectives.

Generally speaking, there are two types of things you’ll get to work on as a designer. The first is stuff that already gets designed a lot: cars, record sleeves, logos, lynx cans and whatever. These are probably the things you got taught to design in school. Designers have been working in those industries for a long time, so everyone involved in making them knows why good design is important. Sure, not everyone is going to agree on what good design actually looks like, but everyone wants it.

The second types of things are the stuff that probably hasn’t ever had a designer near it. Things like phone contracts, plumbing fittings and probably every website you had to deal with in university. Often these things are important and make a real difference to the people who use them, but nobody working on them thought they had the time or money to get a designer involved. For these projects you’re going to have to convince the people involved that design is worth bothering with, that it can help them with the things they care about.

So a really good design portfolio does two things:
1. Shows off your skills and taste.
2. Demonstrates you understand and can explain how your actions made the thing you were designing better than it was before.

Most portfolios seem to commit 100% to either one extreme or the other. Beautiful catalogues of faultlessly retouched renderings, or dry and super detailed stories of processes and documentation. But everyone I know who hires designers is looking for portfolios that combine both.

Practically, this means you should choose projects for your portfolio that are the sort of thing you want to be designing. There’s no point showing loads of work you think is boring, you’ll only end up getting hired to do more of the same. Show the work at its best, but also be sure to show it in the context of where it’ll be used: Mobile apps are used by people when they’re out doing things; a magazine cover that’s going to be sold in a supermarket has to do totally different things in order to look good than one being sold in an art gallery. Show some of the rival products, or what the old version looked like before you got involved. A few photographs like that can explain the backstory way more easily than writing a load of explanation text. But also be realistic about what you did. If your starting point for a project was wanting to experiment with a 12 meter roll of Day-Glo paper because you bought it non-refundable and then it turned out not to work with your printer, just be honest about that. You don’t get to choose your client’s problems; the important thing is the consistency you have in how you approach solving them (note: this definitely never happened to me).

You don't need to worry about listing all your technical skills. I’m just going to assume you can use some graphics software (and are happy enough with a computer to pick up new apps without much trouble). I’m going to assume you know how to use a camera. I’m going to assume you know what grids are. I’m going to assume that you’ve played around with HTML and CSS enough to know what it looks like. And don’t fill it with buzzwords either, that’s what LinkedIn is for.

When it comes to showing your portfolio in a job interview, focus on two or three projects (but make sure you have a couple more available if you need them). Get straight in there and show the thing. If it’s a website, get it open in a browser. If it’s a book, bring a few copies with you to hand around the room. Make sure to point out the best bits of the design. Maybe it’s a graphic detail that refers to the client's most famous product, or maybe its a really simple change in wording that made the work usable for people with disability issues. Then work backwards, explaining the problem you tried to solve with the design. Show some sketches and prototypes and maybe some experiments you tried that didn’t work. Then explain why the experiments didn’t work and show how you changed your idea in the finished result. If you worked with someone else, mention it. Being able to collaborate with a team is a good thing but lots of otherwise talented designers are shit at it. So explain how you worked together and who did what.

If the interviewers ask you some hard questions, don’t lose your confidence and assume everything’s fucked. If the interviewers didn’t like your work you wouldn’t be in the room. What they're trying to do is push at the edges of your knowledge to see how you respond to being challenged, being uncertain and not knowing the answer to things.

Unless you work in one of the giant agencies, you’ll probably spend a lot of your time working in teams with people who aren’t designers. Engineers are going to know more than you about how things are made, managers are going to know more than you about business priorities, researchers are going to know more than you about how people use the product. You’re going to need to collaborate and learn from them, and get them to trust you. A designer who gives up the first time they’re challenged isn’t going to make good work, but at the other extreme nobody wants to work with a dick that refuses to listen to people around them. If you can learn from those you’re talking to, and adapt your ideas as a result, you’re golden.

Again, don’t worry about sounding clever or sophisticated. Half my career has been based on watching people struggle with a thing for a while, then pointing out that if you need someone to read text quickly at a distance, it works better when you make the words really short and the letters really big. It’s OK to say obvious things, especially if everyone else in the room is too self-conscious to.

And finally, don’t panic if you haven’t got any experience of working in the exact same area of design as the job is in. I mostly work in digital service design but I’ve hired people with backgrounds in fine art, industrial design and typography over experienced interaction and service designers because their portfolios and attitudes were really strong in the areas I’ve talked about above. We’re all figuring it out as we go.