I happen to have spent a few days recently with a very tidy friend - she and I both have two energetic boys under 8 but her house always looks like something out of Home and Garden and mine always looks incredibly messy. I always wondered how she did it!
Observing her, what I noticed - and none of this is rocket science:
She always always puts things away - even when we were running late to her own child's birthday party, she made him put away the toys he was playing with. I just wouldn't do that - I would leave it for later (then not do it!) Similarly when we unloaded the car after the party, everything went away straight away. Again we would have flopped and opened presents and dealt with it later (or not!)
Every single thing has a place and everyone knows where that is.
She is more comfortable saying no to her kids than I am and has stronger boundaries. There are some toys she won't buy for her kids because she doesn't want them cluttering up the place and she has very clear rules - e.g. Lego never goes outside the playroom.
I found it fascinating seeing this up close as I have always secretly wondered how she does it.
I am now trying to decide whether I actually care enough to try and be more like this or not!