Kindly proofread this paragraph

[new2grammar]

The core responsibility would be to understand client's needs and offering pro-active ideas to grow their business. Accordingly chalk out the efficient media plan to achieve client's objectives.

[stuartnz]

The core responsibility would be to understand client's needs and offering pro-active ideas to grow their business. Accordingly chalk out the efficient media plan to achieve client's objectives.

I'm not a teacher but I would suggest something like this:
"The core responsibility would be to understand the client's needs and be pro-active in offering ideas to grow their business. This involves chalking out (or drawing up) an efficient media plan to achieve the client's objectives."