In addition I'll list things I want to work on the next day, next week, next month, and even longer term goals. I'll jot down specific concepts I want to focus on, such as tunes to learn, exercises and drills, ear-training, ornamentation, increasing speed, timing, rhythm, arpeggios, scales, improvisation, analyzing the shape of a tune, books I want to look at or read, research I want to do. Basically planning so I know exactly what I need to do next time. This will help me have a well-rounded practice regimen.
I also want to write in the journal immediately following a session or jam. How it went, how I felt, what I played, what I couldn't play, what I didn't understand, what my physical and emotional state was, what tunes I liked or didn't like, what was frustrating, where I had light bulb moments, and so on. I currently attend 6 to 8 jams a month (20 hours per month) and it's easier to identify weaknesses and deficiencies immediately after playing in such an environment.
Ultimately, by keeping a practice journal I hope to have a feeling of accomplishment as I look back and see my progress over time. It will keep me honest about what I really need to be working on and will challenge me to continue to push myself further than I was the day before.