if you have dual responsibilities in a company like administrative officer and executive secretary, how can you focus on your objectives?

It's tricky...you have to look after both areas, there's no two ways about it. You have to make both parties happy and time management is always going to be a challenge. Getting in there early before everyone else does help in terms of planning and preparing for the busy day ahead, and keeping away non urgent things for later also helps. I'd say to maintain composure and a friendly attitude at all times, and provide updates to people in case things are getting delayed.

I can be focus by looking for what is best way of making my job easy.
Do first the importants matter in job and follow some other less important.
By that i can maximize my job and and responsibilities.
Great planning and scheduling also is vital especially in simultanuous tasking.

I would prioritise duties depending on their urgency and relevancy and plan a time table of tasks and duties to be done on the first priority taking care that all responsibilities are well taken care of and accomplished on time efficiently.

You have to set your objectives, then give priorities to the ways towards objectives.