On a level & at a level

Hi, Would you clarify the difference in the meaning or in grammar between these two sentence.

1. Many times, I saw these two - on a level and at a level- used, but remain clueless about the

difference in the usage. Pls. clear off the whole confusion I have and thanks for that.

- Think on a practical level in regard to your emotions

- Think at a practical level in regard to your emotions.

2. what other prepositions are fine in this case below instead of '' with''

- Be soft and gentle with your words and actions.

3. what is the difference in meaning between these two.

- I finished my work.

- I got my work done.

thanks