First of all, build marketable skills
At least on the beginning, you need to be aware of what the market is looking for, and where you can fit. Coding in some way or another is essential for this. Depends on the level of specialization you want to achieve, this would be C++ (development of high-performance algorithms, for instance in finance), Python, R or SQL (data science and business analytics). Some data science jobs may ask you for Java and so on: do it at your own risk, since that might be a position a bit further from modeling.
Another important skill is communication: you need to be able to understand other people’s needs and communicate your needs and the solution to their problems. If you are coming straight from academia, chances are hight that you had to give some lectures to experts and teach some courses to non-experts. In many countries, PhD students have to teach to students beyond their field. This is particularly common in maths, where pure math PhDs are usually teaching business students. It’s useful to find out this kind of opportunities during the PhD, so don’t hesitate.
The message that needs to be delivered to the decision makers of the place you want to work is this: you have to show them that you can get work done, and that your work is bringing in revenue or reducing costs. Anything else is utterly irrelevant to them.
Finding a job
There are lots of websites out there, which I am sure you are familiar with. I have had great success with indeed.com and their localized versions. Be sure that you understand the job requirements, and read between the lines. Sometimes (rather often) recruiters do not understand a lot about the requirements, so they just pull in a long list of requisites. A good recruiter will look at your CV and maybe even call you if they see that you could fit in their team, whether you fit on their shopping list or not.
The estimates vary, but it is generally agreed that most of the jobs never make it to the job boards. I know, that’s disappointing, but you should be aware that the best way to get a job you will enjoy is through networking. Go out and talk to people, nowadays every major city has meetups or other interest groups where you can find people with common interests. Don’t hesitate to pull in your network: for sure by the time you end your PhD you have a solid network of people to rely on.
It is always useful to build a name for yourself, so don’t hesitate on participating in as many public speakings opportunities you get, specially if it is for a wider audience. Who knows, maybe someone will offer you a job after your talk…
The interview process varies wildly: some places may ask you to prepare for a coding interview, while others may interview you and then do an offer. Usually there are at least three rounds: a first round to do a quick assessment of how suitable you are for the job, a second round to see that you know your stuff and a third round to see the final decision maker.
If you are invited to a coding interview, it is highly advisable to get some practice in websites like Codility, Hackerrank, Codewars or Project Euler.