Assalaamu alaykum. Could you please give me some advice on how to avoid pressing my forehead on the ground hard? Whenever I feel like supplicating while prostrating in or outside the prayer, I have the tendency to press my forehead on the ground, then when I get up, I feel a little lightheaded.

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger. 

The Sunnah of the Prophet, sallallahu ‘alayhi wa sallam, is to let one's forehead and nose rest on the ground while prostrating in the prayer. It was narrated on the authority of Abu Humayd As-Saa‘idi, may Allah be pleased with him, that he said, “When the Prophet, sallallahu ‘alayhi wa sallam, prostrated, he would place his nose and forehead on the ground, and he held his forearms away from his sides and placed his hands parallel to his shoulders.” [Abu Daawood and At-Tirmithi]

However, such placing of the forehead and nose on the ground should not be exaggerated. In fact, some scholars considered that such exaggeration is the act of the ignorant. The Maaliki book Sharh Kifaayat At-Taalib reads, “It is sufficient for the praying person to place a part of his forehead on the ground without pressing it hard to the ground to an extent that it affects his forehead. This is disliked, and it is what the ignorant men and the weak women do.”

Ibn ‘Arafah said, “(Imam) Malik held that it is disliked to press his forehead against the ground.” [Al-Mukhtasar Al-Fiqhi]

Sharh Az-Zarqaani ‘ala Mukhtasar Khaleel reads, “He should not press it, and Sa‘d ibn Abi Waqqas said that it is disliked and that only ignorant men and feeble women do this.”

So we advise you to stop exaggerating in the prostration, and it is enough that you place your forehead and nose on the ground without pressing them. This is a simple matter that does not need to be explained. If you asked a child to place his forehead on the ground without pressing it hard, he would easily understand what you mean without asking how to do it.

Allah knows best.