That seems to be the #1 question. Where do I start? Unfortunately this question isn't as easy to answer as you might think. I have come to the following conclusion and forgive me for going all Feng Shui on you.
Clear the area that blocks you most first. What is that area? I don't know. Think about it. IT might be your bedroom, because that is where you regenerate. It might be your bathroom, as you find your focus when getting ready for the day. It might be your kitchen, because this is where you hang out when friends stop by. It might be your laundry room, because HUH? The laundry room?!?
Here is why. I always know, that I hit rock bottom when I can't keep up with laundry. Laundry is my famous last man standing. When laundry falls all else was lost a while ago. I've known this for years, but only recently have I discovered that filling my laundry room with all these things that don't have anywhere else to go makes me no want to go down there, which keeps me from doing laundry which makes me feel I can't ever get anything done which...you get it.
So with a whole house to clean, meals to cook and I don't know what else, a few days ago I took 30 min to get started on that room. I only cleared a fraction, but enough to make me feel better. By now half of it is cleared, I can access the washer and dryer without a problem, I don't have to step over things or walk around things with a basket full of laundry to get in or out of the room and let me tell you, IT FEEL SO MUCH BETTER ALREADY!
So what ever it is that blocks you. Find it. And no matter how insignificant it might seem. Solve it. If that doesn't change things, you might still have to keep looking for your personal starting point.
Once you get your energy to start flowing things will get easier!