For managing the amount of WIP and ensuring the right WIP gets done to work towards your MVP I like the technique of Storymapping.
First, it uses post-it notes which makes the process very visible, shared and easy to modify.
Second, it ensures people have an overview of the exact work needing to be done preventing a lot of time being put in parts of the product that aren’t of primary importance for the first to be released product.
To keep track of what everybody is working on, Trello is a good solution.