What would be my advice to myself when I was starting.
Here are few things from my subjective list.
Dos:
1. Spend most of the money on monitors and acoustics. For the obvious reason, you need to hear what you are doing. High end monitoring with a good acoustics is a key to this. Confidence you can get in your decisions worth every penny. No only in the daw, but also when buying another plugins or hardware.
2. Train your ears. Invest at least few months on a daily ear training. Frequencies, Compression, Reverbs, Saturation.
3. Understand what are the differences between producing, mixing, mastering. This is sounds so obvious, but for some time I was trying to learn production from mixing channels, and this was a mistake. While plugins maybe the same, but techniques and goals are different.
4. Learn the history of mixing / recording / production. You need to understand why and when to use this emulation or that hardware.
5. Use 96khz for you projects if you can. Many plugins don't do oversampling, with 96khz you get a better sound.
6. Keep only plugins and hardware you actually use. Sell the rest.
7. Real analog is better than an analog emulation, but plugins are good enough. Buy hardware only for the most important things.
And the don'ts:
1. Don't go crazy with audio interface for DA or cables. Many monitors nowadays have digital processing and a digital input, use them instead of analog inputs. When working with digital, doesn't matter which audio interface you have there will be no difference in the fidelity.
2. Don't buy the do-it-all plugin when you are a beginner. Example, Pro Q3 or Kirchhoff. These plugins give you an unlimited freedom, but as a beginner will be doing random moves. One trick pony plugins are better for beginners.
3. Don't buy many emulation plugins of the same thing. Modern analog emulations are very close to each other. Keep one emulation plugin for each hardware.
4. Don't spend more than $40 on a plugin rule.
5. Don't buy subscriptions or bundles. You will have crapload of plugins that will only confuse you.
6. Don't be obsessed with an analog hardware. Analog workflow is a pain after you get used to plugins.
You are welcome to share yours.