25 Tips for New Developers: Advice from a (Mostly) Self-Taught Software Engineer

Health

First off, take care of yourself. Sleeping the optimal amount for you will make you more alert and focused throughout the day. The same thing is true for drinking enough water. I also try to eat protein, fat, and carb balanced meals frequently throughout the day. I run most days and try to do other strength-based workouts too. Plus, I take a spa night on Sundays where I do face and hair masks and teeth whitening.
Don't take health advice from me -- it's not what I do. Still, I do think prioritizing your health is one of the most important things you can do for your productivity and overall well-being.

Scheduling

As far as scheduling goes, I live by my Google Calendars. I put everything on there - I'm the person that sends my friends GCal invites for every hangout session. Otherwise, I'll forget. It's as simple as that.
I have three calendars, one for my personal life, one for We Learn Code (my company), and one for my day job. Sometimes, I'll forward events to my personal calendar, so they're all in one place. If I'm super overwhelmed, I'll calendar block everything. So, I will have every minute of my day, even free time scheduled in. I don't do this often now, but it used to be really helpful for me to see my schedule upfront.
Note: this was a week where I was in between jobs and had a lot I wanted to get done. I was also on vacation for the second half of the week.

Prioritization

In order to prioritize what I am going to work on, I first ask myself if it's something I'm passionate about. If it is, then I think about the time commitment and what I wouldn't be able to do if I decided to take on the new task. So, if I were to pick up a new freelance client, I would have to postpone working on an ebook, for example.
My greater goals and priorities have shifted over time. I initially wanted to build a bigger audience, and the activities I took on were correlated to that. Now, my financial situation has changed a bit, and I rely on my side-work being a larger portion of my income. In the future, I may prioritize more free time, which will change things again!
To help me prioritize, I use toggl to track my time spent on every project I do -- not just paid ones. I'm even timing myself writing this post right now. I do this so that I can see where my time goes, which inefficiencies exist, and the payoff of each activity.
For example, here's my Toggl report for the week I'm writing this. Each of my projects is color-coded, and different views show my hours worked per day and listings of each activity by time.

I also ask myself, "What are the three most important things for me to get done?". For my side work, I have three big to-do items for the week. For my day job, I do three per day. I use a pinned Google Keep sticky to keep track of these things, and I have another sticky with any time-sensitive tasks I need to do that day. Mostly things that won't take long, but need to get done then and there. Having just a few essential things to work on helps me to stay focused. I try to only work on what I've set out to do at the beginning of the week. I'm pretty dedicated to getting these few tasks done and worry a lot less about everything else.
I read the book Essentialism recently. It got pretty repetitive at some points, but it does a great job at explaining how to prioritize and why prioritization matters so much. Just do what's essential, nothing more nothing less.
Also, I do not do it all myself. If there's something that makes sense for me to have someone else do, I will hire a service to handle those tasks. I do wash and fold for my laundry, I used to hire a cleaning service for my apartment, and a large portion of my diet is take-out. I'm in a privileged position to be able to outsource some of these pieces of my life, but it allows me to do more of the work that fires me up: teaching code.