Didn't like RainX myself. Only last a few weeks, and smears like heck when it's going off.
Try Gteqniq G1 Glass treatment. Costs about £10, and lasts upto 2 years. I used G4 Glass Polish, and G6 Glass cleaner too. Not the cheapest combo overall, especially just for glass, but it does the job, and does it VERY well. Barely ever need to use the window wipers. Of course, G1 is really for if you generally drive at higher speeds. G5 (I think) works better at lower speeds, but only lasts 6 months or so per application. Still gonna be better than Rain X though. And probably easier to apply than G1.
As for the actual paintwork, as said above, the two bucket method, with grit guard, is meant to be the best. I personally don't bother everytime, but do occasionally employ this method. I always use a lambswool mitt, or microfibre wash sponge thing. I found Meguires Hyperwash to make for an excellent car shampoo, as well as snow foam, and you really don't need to use much, it is very concentrated. It isn't overly cheap though. But will last a decent time. I usually rinse the car first, then snowfoam, then wash with mitt, then move onto the next process.
IronX, Autosmart Tardis etc... They are bug & tar removers, and are really great. But you probably wont need them at this stage on a newer car. But handy to have for later.
Claying the car before polishing will certainly help ensure you have a nice, smooth surface to start polishing with. Halfords do a decent meguires starter clay kit, that comes with a bottle of quick detailer as your lube. It's a good combination, but the QD is quite expensive to keep up using as a lube. Once you bottle is half empty, top it up with water. Once it's proper empty, then just use water with a bit of car shampoo in it, and that should do the trick nicely.
I'd probably snowfoam again after this point, just to get rid of any residues or anything, then dry.
Then you would polish your car. I have had great results with AutoGlym Super Resin Polish. It's not the best polish out there, but it works well by hand, and is a decent place to start. If you catch the bug, and start getting really into it, buying polishers and stuff, then there are other polishes out there with different properties, depending on if you just want a good shine, or paint correction etc...
After the polish, I use a good sealant. I have had good results with Menzerna Power Lock. Easy to apply, easy to buff off, great results.
Then finish with a wax. I have used Meguires (I think) NXT Tech Wax before and it's been great, giving a lovely shine. But there are better waxes out there too. So worth having a read up. Something like Collinite 476S should be great.
Now, that's really about as far as I'd ever go, and even then, I rarely go that far. I do use the Gtechniq on the glass though, as it really is fantastic stuff. You can get almost everything from Halfords, but the Gtechniq you'll likely need to order online, so might just be worth ordering everything else at same time. But it wont be cheap setting up for the first time. Some steps you could drop initially. Like the claying I guess, but then that does make one of the biggest differences to the final result, it's kinda worth just paying for. Polished bliss do free delivery on everything, so might be worth checking them out for some orders, particularly smaller ones. But they don't do the GTechniq stuff, for that I usually use
http://www.cleanyourcar.co.uk/ But other outlets are available.
