I like Meguiar's also. Probably not a best if going for a show car shine but their NextGen Tech Wax (or something like that) has got to be one of the easiest to use, longest lasting waxes I've tried.
For washing though I tend to go in a bit different direction than most. If really dirty spray off the loose stuff. Then wash with almost straight water with about a drop of one of Meguiar's car wash soaps in it to make the water flow better. Either use multiple buckets or change the water often. All of this definitely in the shade. Especially if the water is as hard as here. Keeping it wet helps but with really hard water the spots still build regardless. Shade tends to keep them soft and out of the paint letting a slightly damp towel wipe them off easily. Cool paint is also harder than when warm. This would be much easier if they'd still put floor drains in garages.
Last dry with microfiber or pure cotton terry. Chamois's work but always seemed to strip the wax faster. Even the syntethic one.
Some of this may be excess if your water is normal. Around here it's very hard. If I remember correctly it runs something like 16-18 grains/gallon of calcium where I believe around 6 is more typical. The local water company quit publishing this particular number. I tried using one of the Mr. Clean car wash system filters which worked well, though they were only good for 1.5-2 washes. Didn't like the rest of the system. I believe Griots sells a much larger filter system for this. I'm tempted to try one though if it only upped the number of washes slightly the cost would still be excessive. A water softener helps though since they only trade sodium for calcium is still spots. The spots don't seem quite as tenacious, however.