The word "us" here refers to God. God was saying what he intended to do. The pronoun "us" is plural. Possible reasons for this plural pronoun are: 1) the plural form suggests that God is discussing something with the angels that make up his heavenly court; 2) the plural form foreshadows the later New Testament implications that God exists in the form of the Holy Trinity. Some translate it as "Let me make" or "I will make." If you do this, consider adding a footnote to say that the word is plural. (See: [[rc://en/ta/man/translate/figs-pluralpronouns]])
These two phrases mean the same thing and emphasize that God made mankind to be like him. This verse does not tell in what ways God made people to be like himself. God does not have a body, so it does not mean that people would look like God. AT: "to truly be like us" (See: [[rc://en/ta/man/translate/figs-doublet]])
The way that God created man was different than the rest of creation. This will be described in the next chapter. Do not specify that he created man by simply speaking as in the preceding verses.