How far do you want to go? Is it for the occasional track day but mostly road use, or more dedicated track car? This is very important to consider in advance and also your budget.
You can develop it in stages depending how serious you want to get. Here are some starter ideas:-
1. Brakes, serivce the calipers and fit quality discs and pads.
2. Suspension, check all mounts and bushes are in good condition. You could consider replacing with poly or other harder bushes (this will generate more cabin noise on normal roads). Then decided on what shocks, springs, torsion bars and anti roll bars you want.
3. Engine performance, minimum of good serivce and tune up. Might want to consider performance exhaust, panel filter upgrade and Promax or similar chip.
4. Weight reduction, removal all carpets and sound deadening, weight bucket seats in front, remove rears. The car will be extremely noise in cabin after this.
5. Some form of roll cage ansd harnesses
6. Fire extinguisher
There is no simple answer to your question, just more questions
But before any of the above get some track driving tuition, and ask the instructor about potential tweaks he might recommend.
Have fun.