Man affirm his belief by 

Shahada, salah, fasting, zakath, haj

Jubbah, ijab, beard, cap, turban

Following the commands in the hadith
Following five pillars of Islam in the hadith
Following farl and sunnah in the hadith

Reading Quran and hadith 

Spot on your forehead 

Islamic appearance 

Your serious face, rolling eyes 
Aqeeda, yakin

Ihtikaf, istigfar, sajada and Thouba

However without serving humanity affirming your belief alone is not sufficient for the highest realization 

Man REALIZE his belief by 

Being sincere in your dealings 

Being modest in attitude 

Being peaceful in behaviour 
Being content in desires 

Being sensitive to injustice 

Being selfless in character 

Being simple in attire 

Effacing your achievements 

Shun recognition to supress your ego