Even more than with giving opinions, sharing personal experiences is something we often ask students to do in class without spending much or any time on specifically giving them language to do so. Phrases that you could teach and practise like “In my experience,…”, “I generally find that…” and “Just the other day,…” are also invaluable outside the classroom, including in EFL exams like IELTS and FCE. With all that in mind, have just published an article with other useful phrases and many teaching ideas, and posted 12 worksheets on the topic, including ones practising other useful language like social issues and news vocabulary:
Sharing personal experiences in EFL classes (with list of useful phrases and game ideas)
If you are guilty of the other bugbear of mine that I mentioned above, asking for opinions without teaching language for answering, see here for similar links.