how can we do seo for jobs & career websites?

Do your keyword research

Check what your competitor's are doing

make website easy to navigate

optimize job's and careers category

What I know of targeting local traffic is by creating local content, location, getting local citations etc. But this takes time (in my case, it is a travel blog. Audience and travel locations didn't matter)
Whereas, in your case it very specific for job search. First segregate the geographical areas where you want to cater your business, get some tags of regional maps on Google.

There are specific SEO tools that are focused on developing local search results. Like Google's algorithm, these factors too keep evolving.

'Moz' shares its annual survey results of 'factors influencing Local Search Ranking'. The results includes world's 35 to 40 top local SEO experts. I highly recommend you to take a look at it to be able to get better insights into how and what factors can help you get better local search visibility.

Local and Targeted SEO is best For Offline Jobs