Invest in some good quality products, as if you want your car to look nice, quality and care is the key.
I personally use Auto Glym as all their stuff does what it says and gives very good results.
Start off with some Auto Glym Car Shampoo in a bucket of hot water (make sure you clean the bucket out first) and also you can sue another bucket to clean your cleaning apparatus out with, but I tend not to.
Anyway, hose down your car firstly with a hose (obviously) and agitate and big lumps of dirt and try to get as much excess crap of as you can.
Then apply liberal amounts of your hot soapy water combo on the car using a lamb’s wool wash mitt. Don't use a sponge as these trap dirt particles and drag them along the paintwork and scratch it. A wash mitt can be bought from Halfords for £7.
Start from the roof and down and make sure you clean all the glass, lift the wipers up, get in the mirrors etc etc but leave the wheels, also make sure you spray your wash mitt out from time to time to avoid dirt build up. You can also, using an old sponge get in around your arches and get down and clean your sills. Then rinse the car off using the hose.
Next step, spray down the wheels like you would the bodywork and use a sponge (don't want to contaminate your mitt) to apply the hot soapy water. Then rinse the wheels off. You can also use a wheel cleaner, I use AutoGlym Engine and Machine Cleaner as it's powerful but non acidic. Now rinse off your wheels.
Next step is to dry the car. Do this using a chamois, rinsing it and straining it regularly and get rid of all the excess water. This does two things; it gets rid of unsightly water marks and also gives you a nice dry base to wax/polish on.
Apply Auto Glym Super Resin Polish using Meguiras application pads. Apply in a circular motion a panel at a time. Press harder on deep scratches and blemishes. Leave the polish to do its thing while you back to black any black trim with Auto Glym Bumper Care (applied using a cloth and buffed off using a clean cloth) and also Auto Glym Glass polish, on the inside out outside of your windows.
Now remove the Polish using a polishing cloth. I've never experimented with polishing cloths and just use Halfords own, but I'm sure someone can suggest better ones. Anyway, buff off all the polish on the cars bodywork.
If you want to take it a bit further you can apply Auto Glym Deep Gloss Shine. This is a liquid hard wax that needs to be applied in a VERY thin layer; otherwise it's a bitch to remove. This does give a slightly deeper shine and makes the car easier to clean.
Finally use either Auto Glym Tyre Dresser or Bumper Care on your tyres to give them a nice black shine to them.
All of these products are available from Halfords. Just take your time with it and don't be lazy (i.e. if you drop your mitt or cloths on the floor then throw them away as they'll be contaminated). Try and keep your wheel cleaning and bodywork separate as to avoid contamination. Also don't clean your car in direct sunlight or leave the polish/wax on too long.
Anyway, give that a go and you'll deffo notice a difference.