Tips on giving feedback as opposed to simply criticizing

Based on what I’m learning, when I give constructive feedback to others, I am – or should be: Reinforcing or encouraging a more effective way, redirecting a behavior or pointing out a more productive way, ensuring appropriate standards are set , and / or helping the recipient prepare for better performance. (These are from my notes.) With that in mind, how can I be sure that I’m not just giving someone my advice or personal opinion especially when ‘providing feedback’ to co-workers. I know ‘timing is everything’ but I’m interested to hear personal experience or tips on this. I’ve come to realize one of my ‘faults’ is I give too much unsolicited advice and that is one of the reasons I’ve chosen this course – to learn/improve.)

To be frank, I should have waited until I'd completed this course (ML120).  I've realized I was pre-mature in my question and the material does a solid job of helping me.  But I still value hearing from others on this topic!