Excited as ever for this. Got my toolkit ready. Trying to decide if I want to aim for something besides speed this year; maybe visualizations, or literate code. Given my current work, I probably won't focus on a new language.
My “toolkit” is Perl and an Emacs expansion that adds some boilerplate reading text files and stuffing them into a list.
Edit here's what's expanded when I type "aocinit" an empty buffer:
https://gist.github.com/gustafe/27be34b3c57728f40101a93a95ce...
Since it's your first year, none of that's needed - just enjoy the puzzles, and search for any useful patterns or tools as you go along. Eric's recommendation is to make the puzzles work for whatever goal you're aiming for - speed isn't necessarily one he recommends, instead recommending it as a tool to learn new languages, or to try new skills, such as visualization.
You don't have to race, it isn't required, but the people who do race are very very quick off the draw - they have scripts which login and download their data file as soon as it's available, then templated code ready to read it in as if it were numbers, as if it were a CSV, and load up some counter variables and arrays to save a few seconds typing, and they skim read ignoring the story, trying to jump to the calculation, code it in moments, run it, get an answer, paste into the site, and verify it. Then download the datafile for part two, skim read the story for part two, modify their code to handle it, run it, get an answer paste that in. First person did both those, all that, in 1 min 48 sec. (!)
Toolkit is mostly "I've done this last year, know what held me up, or what patterns came up several times", you don't need one at all if you're not racing for the first 100 answers.
btw. you can sign up now and do previous year's puzzles if you want to see what it's like.