All objectives must be SMART.
SMART stands for:
1. Specific – Objectives should specify what I want to achieve.
2. Measurable – I should be able to measure whether I am meeting the objectives or not.
3. Achievable – Are the objectives I set, achievable?
4. Relevant – Is the objective relevant to the project?
5. Timely – When do I want to achieve the set objectives?
A lot more information can be found here.