After 8 years experience of waxing my own skis, I have found out the best way to wax skis.
This is solely my own method, compare it to yours and see what differs.
1) firstly, I look at the wax I use, DataWax butane or Holmenkol natural ski wax works best, since I work at the chill factore in manchester most of my slope time is dedicated there. the wax is based on what temprature you are skiing in, 0 to -16 degrees centigrade is your best bet.
2) remove the old wax using a scraper, they are fairly cheap, but if you are on a budget you can always use a ruler.
3) go over the base of the ski from tip to tail with a nylon brush, again they are cheap. do this a couple of times on each ski, this will help clean the ski.
4) use a rub on wax like butta to coat the base of the ski, run the wax up and down the ski with a nice amount of pressure, but not too hard.
5) scrape most of it off using your scraper, you now have a nice coating to protect your skis when you do the proper wax job, step 4 will prevent your skis from being scorched by the iron.
6) set the temprature of your iron to the middle of the wax iron on temprature range, for me it would be 125 degrees centigrade.
7) once the iron is up to temperature hold the wax to the iron soleplate so it drips onto the base of the ski in a nice zig zag shape up and down the ski, if the wax smokes your iron is too hot and you will damage the ski.
8) once you have done step 7, iron on the wax in a straight line, from middle to tip and middle to tail. if the wax seems to dry right where you just ironed on this is a teltale sign that you have the temperature of the iron just right.
9) leave the ski to cool for about 20-30 minutes
10) scrape off the wax using your scraper, again from tip to tail. once you have done this the wax shavings should be binned, do not reuse them. take the nylon brush and brush the ski from tip to tail, repeat this until the ski has a shiny base, you will notice your scraper has a cut out in a corner of it, this is to take the wax off your edges.
11) repeat steps 1-10 with the other ski and that is your skis all waxed and ready to be edged