You're selling your house. It's a big process, and you aren't sure where to start. You need to price it correctly; you need to get it in tip-top shape for all the showings; you need to fix up a few things. Now, many people think of the last item last. In fact, many people put off the last item until after they have the house sold (on contigency, perhaps). There are several reasons why people put off making the necessary updates and fixes to their house, e.g., buying new appliances, sealing the windows. First of all, it's time-consuming to fix up the house. If the house doesn't sell, it may seem for naught. Secondly, it takes money. Again, if the house doesn't sell, it might feel like money that wasn't well spent. Why put in the time, effort, and energy if the house isn't going to sell anyway, the thinking goes.
Think of it this way instead. If you are going to put in new appliances and spruce up the house, shouldn't you have some time to enjoy your freshened-up house before you sell it? In addition, repairing the ceiling or putting in a new stove will attract buyers more readily than you telling them that you will get it down AFTER an offer is made on the house. It's far better for a potential buyer to see for him/herself how great the house is rather than how great the house could be. Who knows? Once you get the house all gussied up, you may fall in love with it all over again and not move after all.
In the end, it's a win-win situation for you to fix up your house before you put it on the market or in the early days of the selling process. The possibilities are endless.