After almost one year without few real deadlines in my life, I think I'm finally learning how to balance my different projects in a way that 1) everything gets attention and 2) things actually are completed. One of the biggest changes I've made is starting to outline manuscripts before I'm done with data generation. It helps me identify what data I need to generate, and makes me think about how many steps are going to go into it.
At some point in my undergraduate training, the idea of making metrics for everything was beaten into my brain. Every so often, I will sit down and make my priority matrix for every project I'm currently working on. First I split them into two types: things which need computation time, and things which need brain time. Each project gets a 1-10 score in several categories, which I assign different weights.
50% of the score is immediacy of the next deadline. When I actually have them. 20% is for length of time I expect it will take to complete. 20% is for how long it's been since I worked on that projects, and 10% is for how important I think it is to its master project. The entire score gets multiplied by the number of tasks that depend on this task. However, I let myself get frustrated with projects and take a break from them, and if I'm inspired on a particular project, I will give it more attention.
So far, I haven't had any deadlines take me by surprise, and I haven't heard any complaints from my advisor that I'm not producing the right data, but with the annual grant review coming up, that may change.