That's smart to take photos and keep notes on each area. I have just started taking pictures of my gardens.

As for year around interest, I usually make sure there is summer bloom, as that is the longest season for us.

Spring:
Crab apples blooming are beautiful. (Fall berries)
Coreposis blooms for me spring and fall.
Azaleas that bloom spring and fall.
Dwarf indian hawthornes. (Fall berries)
Jasmine climbing on an arbor.
I've recently planted some dianthus.
I've ordered some muscari bulbs for early spring.

Summer:
Roses (I have lots), canna, mock rose, salvia, liriope, hosta, clethra, hydrangea, mandevilla.

Fall:
Sedum, asters, and some listed above. I keep saying I'm going to plant some mums, but I just don't know where!!!

Winter:
I always make sure I have some evergreens in my beds (a lesson I learned the hard way).
My evergreens include dwarf indian hawthorne (has berries), dwarf buford holly (has berries), sky pencil holly, boxwoods, gardenias, liriope, jasmine. I have a couple of yews but the 109 degree heat really took a toll on them and I'm not sure they're going to make it.

Of course, these are not all in the same bed, but I try to think of different bloom seasons when I'm planning a new bed and then tweak it as I see what needs different things (like the muscari bulbs I just ordered).

As summer winds down, this is a great subject to be thinking about.

I've been so focused on getting all my new beds filled, I haven't paid attention to sequential blooming--and it shows.

Having filled one of my older beds, I realize now that it looks fabulous in Oct-Nov and pretty poor the rest of the year . . . mostly bare in the winter, and a sea of green in spring & summer, except for the plumbago that blooms all summer. I need more evergreens, and bloomers for spring & summer.

I haven't done much with bulbs since planting lots of daffodils & allium a few years ago, none of which bloomed. I need to try again, I think.

Interesting subject. In the past, I was also concentrating on just getting the beds filled. But now, as new beds go in, I find myself concentrating first on woodies and grasses, then perennials, later adding the bulbs and annuals. This was a revelation for me, I tried putting the bulbs in right away before, and they were never in the right place to ripen without looking horrible. Still need to relocate a few daffs...

This is working best for me so far, along with repeating more plants (not same plants, just same kinds, more than one variety of hosta, astilbe, spiderwort, iris etc. in the same bed) to help tie the composition together.

I find that woodies, with their various blooms, fruits, colored leaves and stems, keep things interesting throughout the seasons. My favorites include dogwoods, viburnums, black chokeberries, clethra, itea, ninebark and KO roses. I'm starting to fall (hard) for hydrangeas, and what finer small tree is there than a crab for a Chicago winter?

I have the single pink KOs, underplanted with orange profusion zinnias this year. The bed is edged with lady's mantle and Purple Emperor sedum. I like to experiment, leaving room for annuals. That was last year's lesson, LOL.