Performing your own window repair can be a delicate procedure, as you're working with a fragile material. It can also be somewhat of a stressful procedure, as you'll need to get a new window in place as soon as possible to not affect your standard of living negatively by cooling down your house and making it more unsafe. To ensure a result that both functions and looks as good as possible, there are a few things you might want to keep in mind while you're performing your glass repairs.
Preventing further cracking
If your window merely is cracked, you don't necessarily need to replace the entire window. If the crack is very thin, it might be enough to cover it with clear tape made for glass. However, if your window is a subject to substantial cracking, you need to replace it. The worrying part about this is that while you're waiting to receive the material to replace the window, the cracking can get worse. To prevent this, you should use a razor blade or window scraper and cut a line around the crack. This will prevent it from growing outside of the mark you've created. Just make sure you don't apply too much pressure; a scratch is enough to achieve the desired effect.
Taking care of the window frame
When replacing the window, you also need to think about other things than the glass. For your window repair to be as effective as possible, you also need to take care of the window frame. If your window frames are made of wood, you should make sure to sand them on the inside and treat them with a wooden treatment after you have removed the old window glass. If your glass was completely broken, you might need to sand for quite some time to remove damages the broken glass has created. Clean the wood off with a cloth before treating it, so that no particles from the sanding get under the treatment.
Treating putty with oil
After you have replaced your window and the glazing has hardened to the window and the window frame, you might find yourself with another problem. If you haven't been careful enough with the glazing putty, you might find that streaks of it have hardened on the glass surface. You shouldn't try to scrape this away as it might damage your new window. However, try soaking it in grapeseed or linseed oil and let it sit for a few hours. This will soften the putty enough for you to be able to just wipe it off the window without risking cracking it.