Beginner machining tips, learned the hard way

View the entire project including tons of video:
I've recently been learning the basics of CNC machining. That's a kind of funny sentence if you're not familiar with the terms, so let me explain. Machining is using fancy tools called mills to grind and cut away bits of metal. It isn't the easiest thing in the world to pick up over a weekend, there are lots of little things to learn.
I've, only completed one project so far. As you can see in the video above, I've already gotten a lot of beginner mistakes out of the way.
I started off, seeing if I could get the job done in a somewhat lazy way. I didn't study for ages, nor did I take any classes. I just jumped in and started trying things. This method has worked well for me in laser cutting, machine embroidery, learning instruments, 3d printing and many other things. However, when it comes to machining metal, those beginner mistakes can be a bit more dangerous and more costly.
Here are the 7 lessons from the video above:
Always remove your vise handle
I've left the vise handle in a few times on accident now. It can jam up against things, or, like this example cause your material to come loose
Upload the correct file
If you have the wrong file uploaded, you'll cut the wrong shape in your metal, which can be costly.
Hold your stock securely
Holding your work down is a big subject in machining. There are tons of ways to do it. I'm not even talking about that though! If you put something in your vise, tighten it up really freaking well.
Actually watch your sims
Most CAM packages allow you to simulate your project. Actually watch the simulations, you can find issues that are much easier to fix before you cut them out of your metal.
Coolant is very important important
Coolant gives you a better result, and prolongs the life of your endmills. Use it, even if it makes your videos ugly.
Use the right tool models in your software
the actual shape of the endmill is important! My software thought my enmill was thinner than it actually was, causing an issue in the results
Learn your feeds and speeds
This is the most important. You can't just plop the tools in there and use defaults from fusion360. You need to sit down and read up on how the tools work and how to figure out the proper settings.
music by Kevin McLeod