Could anyone advise on ways to make thin hair get thicker?

See a dermatologist. Decrease stress. Eat a healthy balance diet which includes protein. Have thyroid levels and iron stores checked. See a dermatologist for evaluation and work-up. Topical Minoxidil twice a day is the only proven remedy to thicken hair. However, this treatment it is not appropriate for everyone (given the warnings, precautions, and contraindications). See and discuss options with a dermatologist.