You can also post specific stuff here. I run a lot of Excel as do many others here and we can probably help optimize whatever structure you are working to build.
I agree. For my VBA needs, 99% of times the Microsoft Office reference site has been enough. Like OP, I have been using Excel at work but we used to have ppl who would do all the coding for us. If a professional programmer looked at my VBA code he would lol hard but it ... works. If it's slow, I can just leave it running on another PC etc.
Find a quantitative or analytical problem you want to solve. Sit down with Excel and try to solve it Every time you get stuck - use Google to search an Excel tip that will show you how
If you want to become proficient at excel (not VBA), I can suggest pick following topics and master them. Spend a day or two on each topic. 1) functions like sumif, countif, sumifs, countifs, nested ifs 2) vlookup, hlookup - using vlookup to reference more than 1 column 3) using index(match) instead of vlookup 4) Pivot table 5) array formulas e.g. using sumproduct, sumif etc. in array formulas 6) different number formats especially custom formats 7) plotting different kinds of graphs 8) using addins like solver and data analysis tools 9) filters, advanced filters 10) for big sheets, using auto/manual calculation modes 11) conditional formatting Above list should be enough - will take around 15-20 days of work. But with above things covered, your excel will be better than 80% of people out there. After covering these, you can start VBA.