An extensive checklist of things to consider:
1. Start with minimizing your reliance on appliances (ie. unused appliances taking up precious storage space).
2. Overstocked cabinets. Make sure your food is on constant rotation and being eaten, not just sitting there collecting dust.
3. Start organizing.
4. Create more counter space (and consider using moveable a kitchen island).
5. Find underutilized space. If you have tall cabinets that aren't being well utilized, a few well-placed shelves can multiply your functional space.