Start with the front hall. It should be tidy and fresh (don't store all your smelly shoes right by the front door). It's nice to keep some fresh flowers or a plant on a small table, or even a bowl of pine cones with some natural lavender oil dabbed on. Something that says fresh, and smells fresh, is very welcoming. And not only for your guests, but for yourself too when returning home.
Open your windows as often as you can, even in winter. It helps clear out the stale air. Bonus - you will hear your neighbours outside which is hopefully comforting, and your neighbours will know you are home so may even pop in for some tea.
Make your house your home. Choose furnishings and fabrics that really say something about you. It shouldn't read like that magazine cover if that's not you. Select personal things, especially in small items and artwork, and your home will help always feel welcoming to you. Your visitors will better understand who you are too.
Make sure you home is efficient - consider seating arrangements, space behind dining room chairs and comfortable beds, linens and towels for not only your guests, but you too.
It is these simple everyday little things in life that bring the most joy, so make sure yours is perfect for you.