A great way to check for alignment between the lesson objective and open-ended task is to compare the verb in the objective with the verb in the task.
Traditional grading of open-ended responses may not be enough to capture student mastery, consider using rubrics and self-reflection to assess.
Because open-ended tasks can be challenging, make sure to validate all efforts by showing praise and recognition with verbal or written feedback.
Consider using open-ended tasks as a way to differentiate for students based on their ability and learning style.
Tiered Assignments uses different assignments for different students or groups of students that have the same content and cover the same objectives, but the levels of tasks are varied according to student readiness.
Product Menus offer students a way to make decisions about what they will do in order to meet class requirements by providing various product options, much like a menu gives a customer many options at a restaurant.
Response journals can be used as a tool because there are no "right or wrong answers" in response journals. Give students blank pages/books that contain questions or sentence stems to help structure student responses. Students write freely to respond to the prompt with little or no guidance on how they must structure their responses.
Interactive Notebooks are used for class notes as well as for other activities where the student will be asked to express his/her own ideas and process the information presented in class. Notebooks help students to systematically organize their thoughts as they learn in a visual and linguistic manner. Notebooks become an active process and a portfolio on individual learning.