Here’s a tip on color combinations. I use photos as a tool for containers or planting areas. You can of course do a “like” or “Contrasting” combination. I take photos all the time in my garden. I save copies and crop some of the plants. It’s best to add the name of the plant as soon as possible. I know I forget what they are sometimes. I then go through the cropped photos and put them together in a collage. Some plants may be able to be divided, others are annuals that I’ll purchase again next year or save. Of course it’s important to know the Sun/Shade requirement. All but one of these plants can take sun or partial shade. The one that needs full shade is the Rex Begonia. I probably will plant that into a separate container so I can make sure it’s shaded. Also that allows me to bring that in the house come Fall. Water consideration also are important.
The best part is that it’s a “Free” way to experiment. No up front costs. You can use photos from gardens you visited, botanical gardens or even internet photos. Then print it out and take it with you to the nursery. No need to buy extras you won’t need. Hope this helps you in your planning.
Do you have a favorite planning method?
Monroe County Master Gardener Association 
Great tip. Thanks. I use a couple of techniques in addition to those you offer. I plan my containers in advance, but also have alternatives planned just in case. Sometimes I can’t find the exact variety or even the plant I want so I list alternatives that should work. Then I can make informed second or third choices when I shop for plants instead of driving all over for that one missing link.
Another technique is to put the tags in the edge of the planter as I create the combo in the spring, one for each plant. Take a few photos to monitor the success of the combo and if you would like to repeat it the next year, drop the tags into the container after you do your fall cleanup. The next spring you have the photos and tags to prepare your shopping list.
I just might try the tags idea. That one appeals to me. I keep all the tags so I just might put them to use. That’ll help me remember the variety as well. Because I do so often know the name but not the variety. Glad your posting. Send us some more ideas!
I am embarrassed to report that my “planning” is a bit helter skelter. I just go to the garden store and see what looks good. I also attend Four Star Consumer Day and look at the combinations. I do keep a garden journal, complete with tags from plants, shrubs, and flowers I have purchased. If I really like something, I note it in the journal. I have kept a journal for nine years and it is great to go back and read my thoughts and study how I have evolved as a gardener. I guess I am the “collector” type of gardener rather than a planner.
I got a journal from a friend one year. I wasn’t successful at it. Guess I’m just not a writer. I admire the effort and commitment it takes to make a garden journal. It doesn’t sound helter skelter to me…sounds quite organized.