‘Thanks for everything’ can be sincere, but it leaves the recipient to guess what you noticed. Specific appreciation makes the attention visible.
Try naming the action and its effect: ‘Thank you for explaining the process again. I was able to finish the application without guessing the next step.’ The message tells the person exactly what helped.
You do not need to make the gesture sound larger than it was. A colleague who shared a useful link does not need to be described as someone who changed your life. Proportionate thanks often sounds more natural than exaggerated praise.
Be careful not to hide a new request inside the acknowledgment. ‘You’re so good at this, could you also…’ may make the appreciation feel like preparation for more work. If you need something else, separate the request and leave room for a refusal.
For a personal relationship, include the detail that only this interaction could have produced: the meal someone brought, the quiet company they offered or the question they remembered to ask.
Before sending your next thank-you, replace one general phrase with a concrete observation. The aim is to show what you valued. A few accurate words can communicate more care than a paragraph of interchangeable compliments.