A personal lookbook and style journal can become a very useful tool indeed! I use Evernote, as you know already, and this might not be the most efficient method, but it works for me. In the beginning this will inevitably take some time, but after the initial work, it is quick and easy to maintain and use. I'll try to give a reasonably short recap of how I do it:
1. To get started, you need photos of your wardrobe's single pieces. This can quickly become a daunting task if your wardrobe is big. Mine is not very big, but I still broke it down into types of garments: Tops one afternoon, laid out in rows on the floor, taking snapshots with my iPhone. Next day it would be skirts etc. I use iCloud and Aperture (iPhoto works this way, too) to get the pics onto my computer. I resized the photos to a similar height of 300 pixels to create thumbnails from them. You can also downsize the photos in Preview, or Paint if you are on Windows. The photos can of course be downloaded to your computer any which way you prefer, including sending them in emails - but that will be very time consuming if you have many clothes.
2. I created a notebook in Evernote called "My Wardrobe". Each type of garment got its own note (one for tops, one for skirts and so son). Each note has a table of 3-4 rows and 3 columns. Each cell has a photo of one garment, this is done by copy/paste from my image folders. When this is finished, you have your wardrobe catalog to pick from. It is very easy and quick to add/remove garments whenever you buy or purge.
Example of note in "My wardrobe. Keep in mind that these photos merely are meant for reference, and my clothes do not look their best in any way:
https://www.evernote.com/shard.....7f7b973390
3. I created another notebook called "Style journal". In this one I collect all my outfit images, and I also use notes to plan my outfits/week. To do that, I typically browse through earlier outfits, and I also select photos from the "My wardrobe"-notes and create a single cell (table function again) where I paste all the images in an outfit. I can also add notes about my plans, details I want to add etc. These notes are never quite alike every week, and I don't bother doing this for every single day.
Example: https://www.evernote.com/shard.....01ad71abc3
4. If i need inspiration, I peek through notes I have built around a specific garment - I always try out several combinations with the same piece when I have time to work (play) with this, and then I create the collages you've seen here on YLF (using Picasa for this specific function). These notes are given labels like "BASIC: Black wrap dress" and organized in "My wardrobe". I also collect notes based on what I wore in a month (mostly low quality phone snaps) etc. Finally, I keep a notebook where I collect ideas I find when I search the web.
This is not a perfect system, but it works for me. I realize that to a lot of people, this takes too much time. To me, the benefit is that I can access my wardrobe from all my devices (phone, tablet, computer), and I like to plan ahead even if I often change my plans again when I feel like it. I hope this information is useful to you, too.