Make sure that the water you are using is mildly warm. Mix the washing liquid with the water. Avoid using harsh washing liquids.
Take the soft cloth and dip it in the solution you have created through the first step. Now use the cloth to dab the solution over the sticker you want to remove. Make sure to cover the sticker all over so that it is reasonably soaked. Also try to dab over the edges to make sure that some liquid passes under the sticker to soften the adhesive there.
Use the plastic spatula to start removing the sticker. Do not use very hard movements. Be patient and proceed slowly while not applying so much pressure or you might damage the window.
If the sticker dries up during your scraping then apply some more liquid with the cloth and proceed with your scraping.
Keep repeating the same procedure until the entire sticker has come off the window.
Once the sticker is off, the window still might look a bit dirty with all the liquid you have used and there might be some remnants of the sticker. Take a clean but soft cloth and dip it in the glass cleaning liquid. Use this to clean the glass. You now have a squeaky clean car window.