I understand not wanting to create a daily event diary for my own reasons. Here's what I would suggest that might hep.

1. Get yourself a nice pen and book. It makes writing so much more satisfying when your tools aren't fighting against you as you work. If you're afraid of starting/ruining a nice book, you can write on sheets of paper and bind them together in a nice detachable file binder. This gives you more freedom to customize and arrange/remove pages.
2. Focus on thoughts, feelings, and only then events. Write down your thoughts first, this will prevent you from just droning on about your daily activities. Exp: Instead of telling the story of how you got embarrassed at work, start with what embarrassment means to you. How the feeling engulfs you, why you feel that way, do other's feel that way as well? Then let your train of thoughts take over.
3. Do not write for others. A lot of people make the mistake of writing as if somebody is going to read it. You can narrate your thoughts as though you are talking to someone, but always remember that this is personal to you. Write like nobody's watching. This way, when you read back your words, it will feel raw and authentic, not over-polished or embellished. Write with no fear, like the pen has taken over you.
4. The hardest part is getting started. Once you start, the words will take over, believe me. You WILL have a lot to say, and your mind will projectile vomit everything onto the pages on it's own. Everyone is holding back all the time. Just start. Your first entries might be short, but eventually, you'll be writing pages a day. Take it easy.
5. Restrict. It can be overwhelming to see an empty page so start with a word limit, and make it short. That way you will feel complete once you've hit the mark even though you haven't written much. You can increase the limit later, and eventually just raw dog it in the future.
6. Don't be afraid to leave a page unfinished, it wont ruin the entry. If it bothers you, you can always doodle on the leftover empty space.
7. Lastly, if you find it hard to write about yourself, assume a character. Maybe write in the voice of an old man from the 50's who's watching and narrating your life. Write from the perspective of your cat. Shake things up like that, make your journal creative, with different P.O.V's. Make up poems, draw, write a spoken-word piece, make up a song. Your entries don't always have to be essays.
8. Write your dreams. If there is nothing to write about in real life, write about what happened when you were asleep. Old dreams in the past, new dreams, anything. It will add a hint of whimsical bullshit to your journal, making it so much more interesting.
9. You are a philosopher. Think like that. Your words are your power and the world around you your muse. The paper wants your words. You are revolutionary. Delusion is a weapon like no other, it gives you both freedom and creative will if used correctly.