This, you will find, is not always easy to do as you will soon realise. They tend to smudge with the best will in the world as they pick up specks of dirt and are quite delicate in themselves
It is worth bearing in mind that pastels can do you harm, as the pigments will pick up dust particles, which can in turn be inhaled if you are not careful. So it is hard trying to save your work.
I personally never use newspaper to store them as the print and the acids in these could really ruin your work. It is probably best to cover your work with tracing paper, which you can buy at good suppliers, that is acid free.
Now you can obtain boards which are acid free, so if you intend to try and store your picture for a long time then I would attach it to a board using masking tape and cover it with tracing paper or even greaseproof paper or tissue. Just remember to strap it down with a tape of some sort.
Always reconsider your work at the framing stage. You may find you prefer to eliminate some. A couple of inches could make a big difference.
Most artists, you will find, probably have a frame of card to put over their work at different angles and decide what they think is best. Does the painting look better with less at the sides for instance? You have to make a considered choice.
Pastel does not work next to glass. If you do this you will have both condensation and find dark spots or patches on your work. To remedy this for framing, your painting would need a mat of cardboard on top to separate it from the glass.
This way your painting will be fine for years to come, without fixing, as long as it does not touch the glass. However, if you really do want to fix your work, you could spray it. Some you will find, have strong fumes and I wouldn’t recommend inhaling them.
Fumes can be very dangerous to your health, so really, if possible, it is better to spray outside, depending on the weather of course. Not that I always do, to my shame! Please, if you spray inside at least open all the windows.