If your car hasn't been exposed too much to extreme conditions, I think a couple of wash n wax sessions should help restore the shine. By extreme weather conditions I mean either parked in sun all the time OR exposed to rains that dries on it (causing some water marks) and you not being a regular car washer. Ofcourse your car would need close examination and then tell you the course of action if it needs correction by an expert but I am giving you a general advice that should work in most of the conditions.
I'd suggest you to invest a bit in getting a good car shampoo and a really good wax. A car over 1.5 million deserves atleast some 5k spending on it to keep it looking great.
Depending on the brand/bottle size, shampoo can vary between 300-1500. An excellent shampoo would be of meguiars brand, above average would be turtle ice and then there are other brands available as well. You can get yourself Turtle ice shampoo, I use it and find it really good.
For wax, I would suggest you to get your hands on either Meguiars Ultimate paste wax (costs between 3200 - 3500 and includes a towel) OR Meguiars NXT tech wax paste (costs 2100 - 2400) OR Mothers Carnauba wax step 3 (costs around 1700 - 1800). There are other brands (3M, turtle etc) as well but good thing about the above listed Meguiars waxes is that they contain slight polishing oils that will also cleanse your car surface a bit as well. Theres a meguiars starter kit as well that includes shampoo/wax/towels but the wax is liquid wax and not sure you'll be comfortable using that and a few other additional things like tyre gel which I am not sure if you are looking to invest on.
If you aren't short of budget, then additionally get yourself a cleaner wax as well e.g. Meguirs cleaner wax (costs around 1500) OR mothers cleaner wax (costs around 1300). Apply the cleaner wax first and then the other waxes that I have suggested above. This cleaner wax will really help remove slight oxidation and restore its look. Please note that this cleaner wax isn't supposed to be applied regularly (applying it after every 3 months is fine).
These investment on waxes will last a very long time for you (a wax jar would typically give between 30-50 applications depending on how thin you apply. So the per application cost is extremely low and with these waxes you dont have to wax every week. Please read up a bit and watch a few videos on how to apply a wax.
Also get yourself a couple of good microfiber towels (they'll be expensive ranging from 400 - 800 but will last long and will take good care of your car surface).
I would suggest you spend some time daily and go through a few pages of this thread every day. I can assure you that you would have learned a lot in a week. There are other car maintenance and getting started tips that you can find a lot specifically in the last few pages from here.
