How to develop a citizen science project?

According to Miller-Rushing, Primack & Bonney (2012), many of the most important and widely used datasets in ecology research have originated from CS programs. Considering the amount of high-quality data that people-powered projects can accumulate once a solid infrastructure is created, CS is known to be cost-effective over the long term. There are many ways to develop a CS project, depending on the project’s scope, functional direction, and objectives. According to Sullivan et al., 2014, there are three key features for developing a successful CS project. First, the balance of data quality and quantity, second, enabling a wide use of the data, and third, engaging a diverse group of partners in the project. An example of a well-suited CS project is a monitoring study designed to detect spatial and/or temporal patterns of species occurrence. When targeting a larger audience, a simple study design that allows participants to influence and work with the study data is preferred. Permitting citizen scientists to both track and compare their observations with those made by others may trigger competition among the participants and stimulate their workflow. According to Bonney et al. (2009), the mentioned features are among the most educational when developing and performing a CS project. Additionally, publishing results in local magazines and newspapers by actively referring to the citizen scientists may increase their motivation on continuing their good work.
Instead of repeating what already has been written down, I encourage you to read the work by Bonney and colleagues (2009) to get inspiration on how to develop a CS project. They point out the importance of a team with people from multiple disciplines, a formal design of protocols including both positive and negative data and emphasize the necessity of educational materials such as identification guides and manuals to postulate a more qualitative research. Furthermore, they suggest practices of volunteer training and recruitment, and refer to webpages that might help to plan, test, maintain, and evaluate your CS project. The links can be found below, and I recommend having a look at their work.

Further reading:
citizenscience.org
citizensciencealliance.org
citsci.org

Bonney, R. et al. (2009) ‘Citizen Science: A Developing Tool for Expanding Science Knowledge and Scientific Literacy’, BioScience, 59(11), pp. 977–984. doi: 10.1525/bio.2009.59.11.9.

Miller-Rushing, A., Primack, R. and Bonney, R. (2012) ‘The history of public participation in ecological research’, Frontiers in Ecology and the Environment, 10(6), pp. 285–290. doi: 10.1890/110278.

Sullivan, B. L. et al. (2014) ‘The eBird enterprise: An integrated approach to development and application of citizen science’, Biological Conservation. Elsevier Ltd, 169, pp. 31–40. doi: 10.1016/j.biocon.2013.11.003.