I broke apart kits at first. And it drives me nuts now! I tried to put some back together, and I have a few that seem to be lost forever.
Now, I use PSE11 and the organizer. When I download a kit, I'll glance at it to see how it's named. Most designers are awesome and name elements staple, stitch, flair, etc and their initials or name. Some even name paper pattern or solid! If the designer didn't, then I will tag the item. This actually takes hardly any time because the majority of designers do it for me!
Then I dump it into my big Digi folder. In that is a freebie folder, and storename freebie folder, Daily Digi folder and designer names. I dump each kit into whichever fits them. If it's a designer I rarely, (or haven't!) bought from before, then it goes into the store folder. If it's someone I buy from a lot, I have a designer folder. The Digi Files I keep by number, and tag the preview with the designers names. Collab kits are Storename_Collabname and everything is dumped in together.
It sounds really messy, but....
If I'm looking for Traci Reed, her stuff is labeled treed_blah blah blah. So, I can easily search in Organizer for treed staple.
I can easily search for keyword paper.
Organizer has a similarity search too, so I can search for similar colors. Or I just search red and see what comes up.
I do tag all templates with # of photos: 1, 2, 3, 4, 5, 6, 7+. Super easy to narrow down what I want.
I do tag all pieces of kits with it's name, and if it's a specific holiday, or Project Life/365/Pocket Page then I add that too. Since I don't exclusively use a kit to that holiday, and I may use a Christmas kit for a regular layout as well (actually, I did last week) putting kits in holiday folders does not work for me.
If it's something I know I'll go looking for by a specific name later, I'll add that tag. Those items are fewer, but I did add viewmaster for the reels, and I've added "blend" for blendable templates or pieces because the word "masks" escapes me.
If it's a favorite, I use the stars to mark it. I've also used the stars to mark a template or paper I want to use.
As for photos, I drop them into one folder by year. I used to divide them by month too, but I hated having to open different folders because I knew something was in the summer, but couldn't remember if it was June or July (usually it would be August or May!). I also hated when vacations overlapped two months, and I had to open two folders. Now I add people (tag) as I import them to Organizer, and places too. I'll add events like wedding or vacation. This has made finding photos super easy. Some day I'll get older years photos tagged as well.
It took me a long weekend to get all my scrap stuff manageable. I'm hoping to get the photos done over Christmas break. But now when I sit down to scrap, I can find the photos I want, and the kit or scrap pieces I want.