Choose an estate agent actually selling houses in your area - get a minimum of three round and don't just go with the highest valuation.
Do all the outstanding DIY jobs that you've been living with. Things that could do with doing make potential buyers think there could be bigger maintenance issues.
Declutter but not to the point of leaving the place without a homely feel. Move anything you wouldn't want in the photos.
Tidy up the front of the house and add a couple of planters, etc if it's bare - think kerb appeal.
Tell the EA you want to have sign off on the listing and photos before it goes live and check what they've put is relevant and actually relates to your house.
Selling and buying at the same time is stressful because you have no control over other people in the process. Try not to worry about the things you can do nothing about. Do what you need to quickly and efficiently.
My top moving tip is: pay the removal firm for full packing. It makes things so much less stressful. You just live normally until a day or two before completion day.
Oh and don't agree to exchange and complete on the same day. Far too precarious and someone can pull out on the day.