When you advise people do it for the pleasure of Allah. Put yourself in the person’s shoes. Understand who they are, where they come from and what their background is.
It is very important to get this information. It is important to be aware of their status. Have they just accepted Islam? Is their iman weak? You need to know this because if you speak to them in a harsh way, you will chase them away. They will go away from the Deen even further than what they are already.
When advising for the pleasure of Allah, be soft and be lenient. When Prophet Musa (PBUH) was sent to Pharaoh, Allah told him to speak in soft and kind words. If Allah told Musa to do this with Pharaoh and He knew Pharaoh will never accept Islam, so imagine how we should speak to those already on the path of Allah?
Don’t be harsh on them with your words, your method and your approach. Their faith may not be as strong as your faith but they are coming towards Allah. This means they are doing well in the eyes of Allah.
Encourage people. Tell them how much they have improved. Tell new Muslims to practice as they are learning and to push themselves as much as they can. This should be based on their surroundings and circumstances.
Your words can make them go away from the Deen or fall in love with the Deen. So be careful with how you speak to people when you give them advice.