Get a big note pad and walk out the house to just out of view. Approach the house as if you've never seen it before.
Can you see the house number or name clearly, can you park, does it look tidy, what stands out, look at the neighbouring houses what looks good that you could cheaply emulate i.e. a seasonal planter.
Parking is a funny one. If parking is a bit restricted when you've got viewings can you move your car/s if you have them so viewers can easily park.
Approach the door does the bell or knocker work, is the doormat nice (a cheap investment for a good first impression).
Enter the house and walk around as if you're on a viewing. Where would you go first, whats your first impression of that space.
Go around the rest of the house and garden as you would if viewing.
Hopefully you've filled a good few sheets of notes and can look at the easy to fix jobs, then assess the ones with a cost against how much you want to invest in time and money.
I go for lots of fresh flowers, house for sale new crisp towels and a new doormat every time.