As an adjective describing a person:
* She is a thoughtful friend who always remembers birthdays and special occasions.
* The thoughtful old man offered to help me carry my groceries.
* His thoughtful gift brought tears to her eyes.
As an adjective describing an action or object:
* It was a thoughtful gesture to send flowers to her after her surgery.
* The thoughtful design of the house maximized natural light and ventilation.
* His thoughtful essay explored the complex issue of climate change.
As an adverb describing a verb:
* She thoughtfully considered all the options before making her decision.
* He thoughtfully placed the fragile vase on the table.
* The artist thoughtfully crafted each detail of the painting.
In a phrase:
* Thank you for your thoughtful words of support.
* She was in a thoughtful mood, lost in her own thoughts.
* The professor's thoughtful lecture inspired the students to think critically.