I like to save the jobs I apply to.
I have an Excel file with the following columns:
Date Job Title Company Location Job Listing Job Listing #2 Cover letter Link Portfolio sent? Response? Optimism-level
I save in it the date I applied, the job title, company, where the job is placed, a link to the job posting (and a second one, in case there are more), my cover letter used for the job (so I’ll know, later on, what I wrote to the company), whether I sent a portfolio or not if I received a response, and how optimistic am I of getting the job.
Having a centralized system for this helps with organizing stuff.