It's been a few years, but prior to that I went through a period where I worked I did a job search 3 times in a little more than 2.5 years. Here's the process:
1. I start by reaching out to people I know - bosses or teammates I've enjoyed working with, recruiters that have proved trustworthy and so on. People who now me and who have worked with me before know the value I bring, even though I don't really excel in any one area. (Early on in my career, this wasn't literally "people I know," this would be more connections through my school.)
2. Since a lot of interview technical questions skew towards Stuff We Learn in University, I usually skim over my college and grad school text books. That way, if someone throws something at me that I haven't really dealt with in 12 years, I can at least have enough freshness in my mind that I can problem solve through it.
3. I practice problems from a "programming challenges" book like the one by Skiena. I do some of these at a computer. However, since many companies do coding challenges on a whiteboard and these are timed, I try to recreate this by doing some coding problems with pencil and paper while timing myself. Whether or not it is a good idea for companies to do coding problems on a whiteboard is an interesting question, but in the course of a job search, but this is the world we live in. Writing programs while timed is particularly stressful, but by practicing beforehand I find I'm able to adapt to the stress better.
4. A lot of the value we provide (both as experienced engineers and as jack-of-all-trades) is best demonstrated through historical examples, and many companies ask about historical examples. So I make sure that I've gone through the important projects I've worked on in my career, and can talk about the situation I was in for the project, what I did, and what the result of the project was.
5. It's hard to know who looks at what in an application submission, but for any company I apply to I write a cover letter explaining why my unique set of skills makes me a good fit for the particular role I'm applying for. As a hiring manager, I saw people clearly copy and paste other cover letters (e.g., I was in advertising and I'd get cover letters ending "... and that's why I want to work in finance"). As an applicant, I write each of these from scratch, going through each item in the job description and saying something very brief about how that's a thing I've done before. (Earlier in my career, I would use examples from undergrad and grad school.) I've generally had pretty good response rates with this strategy.
6. Across all steps, I work in as much as I comfortably can that as a jack of all trades the value I provide is not that I can implement solutions in the area I'm hired for soon after being hired (although, I can), it's that I can handle the uncertainty that comes in many environments, and I can talk about examples where I've done this in the past. Some companies appreciate the value this brings, but some do not. The ones that don't will probably under value you.
1. I start by reaching out to people I know - bosses or teammates I've enjoyed working with, recruiters that have proved trustworthy and so on. People who now me and who have worked with me before know the value I bring, even though I don't really excel in any one area. (Early on in my career, this wasn't literally "people I know," this would be more connections through my school.)
2. Since a lot of interview technical questions skew towards Stuff We Learn in University, I usually skim over my college and grad school text books. That way, if someone throws something at me that I haven't really dealt with in 12 years, I can at least have enough freshness in my mind that I can problem solve through it.
3. I practice problems from a "programming challenges" book like the one by Skiena. I do some of these at a computer. However, since many companies do coding challenges on a whiteboard and these are timed, I try to recreate this by doing some coding problems with pencil and paper while timing myself. Whether or not it is a good idea for companies to do coding problems on a whiteboard is an interesting question, but in the course of a job search, but this is the world we live in. Writing programs while timed is particularly stressful, but by practicing beforehand I find I'm able to adapt to the stress better.
4. A lot of the value we provide (both as experienced engineers and as jack-of-all-trades) is best demonstrated through historical examples, and many companies ask about historical examples. So I make sure that I've gone through the important projects I've worked on in my career, and can talk about the situation I was in for the project, what I did, and what the result of the project was.
5. It's hard to know who looks at what in an application submission, but for any company I apply to I write a cover letter explaining why my unique set of skills makes me a good fit for the particular role I'm applying for. As a hiring manager, I saw people clearly copy and paste other cover letters (e.g., I was in advertising and I'd get cover letters ending "... and that's why I want to work in finance"). As an applicant, I write each of these from scratch, going through each item in the job description and saying something very brief about how that's a thing I've done before. (Earlier in my career, I would use examples from undergrad and grad school.) I've generally had pretty good response rates with this strategy.
6. Across all steps, I work in as much as I comfortably can that as a jack of all trades the value I provide is not that I can implement solutions in the area I'm hired for soon after being hired (although, I can), it's that I can handle the uncertainty that comes in many environments, and I can talk about examples where I've done this in the past. Some companies appreciate the value this brings, but some do not. The ones that don't will probably under value you.
I hope it helps!