To those from North America, this is a familiar paint scheme and logo. My National Park Service Snow Trac is handy to get the Rangers out so they can check on things. The unusual black tracks are government spec LOL.
You do very well getting the paint down. It's something that many are not able to master. Some get the texture or color range wrong. Others mess up on adding the detailing. Yet more can't do two-tone. Are the decals your own? What's the manufacturer and scale?
Most of the time, the decals are of my own creation. I purchased some sets of Microscale decals with various logos (US agencies, fire, police, etc.) to get some specific highly detailed small decals of logos and shields. They have a wide selection and each sheet comes loaded with a huge assortment of decals. Well worth the money.
I work with an airbrush and with rattle cans. I'm pretty particular about rattle can brands and I stay away from certain brands and I'm loyal to others. I prefer older style spray nozzles and stay away from some of the new fangled cans/brands with complex heads/nozzles on the cans. I buy my own spray nozzles and replace many of the ones that come stock on the rattle can. I am particular about the brands of paints I use in the airbrush too. My paint choices are the right ones for me. Others have commented negatively about some of my favorite products but I chalk that up to personal technique and experience.
All of my paint tins, bottles and spray cans get a paper sticker with a number on it. That number corresponds with a notebook that lists the brand, grade and color of the paint. I also note the date purchased (this helps prevent problems due to old paint). I take each paint and apply it on a Formica laminate sample chip. On the back is the number of the can, tin or jar (which cross references in my notebook).
The samples all hang on a old Formica sample board (but anyone can make their own board with a sheet (or part of a sheet) of plywood and finishing nails. This way, I have an actual sample of the paint that I can hold up to something and decide which product I want to use. If you don't have the room to openly hang/display Formica samples, they can be arranged by color groups and stored in a drawer, put in a notebook/binder or placed on a bead chain. The home improvement box stores give away these samples by the hand fulls, so they are easy for anyone to get.
Most important is the ability to have the actual paint color and finish on a sample (which is about as big as the footprint of a 1:64 car) in your hand at a moment notice. Once I decide on the paint (using the sample chip) I can go right to the correct paint with my numbering system.
I rarely have paints mixed by somebody and I prefer to mix my own colors. I'm lucky to have a background which makes that very easy for me. It's not hard to learn with a little research about color mixing and with a little trial and error, anyone (well, almost anyone) can pick it up pretty quick.
Back to decals, I seldom ever buy stock decals from the restoration parts guys unless they have white, gold or silver ink on clear paper. All of the others can be reproduced on a simple HP printer that has a copy or scan function. I can take one three dollar decal and reproduce it as many times as I want on my own decal paper.
Good paint, proper application and patience makes for a good finish. About the only thing I did wrong on this one was to make the decal on the back of the cab a tad too big. I got in a hurry and should have slowed down and reduced the overall size a couple of millimeters.
I'll be coming to you for advice on decals next year. I have several other projects to complete for a start this one. I've never done my own decals, and the project I have in mind uses mostly white lettering. Since home printers can't print white, and I don't want to cut out letters separately, I'll need to brainstorm with someone who has some experience. Don't mind the car itself, that was a mostly failed attempt to color-shift a photo.