^^^ 'Straightly' is in the dictionary, Bob. It is (among other things) a synonym for 'directly'.
What would one need to become a great inventor or scientist without a degree? Well funding for one's research would certainly help, although, of course, some inventions (rather than scientific discoveries) require little research. Also the ability to see the potential in one's ideas is necessary. (For example, when I was about 14, I used an old clockwork motor to power a dynamo that provided the power for an amplifier attached to a crystal set. Hey presto, a clockwork radio! I thought nothing more about it and took it all apart. A quarter of a century later, Trevor Baylis patented something remarkably similar!)
Inventions are probably much easier for an 'amateur' to make progress with than 'scientific advancements'. They generally require nothing more than, say, a DIY workshop and/or a 3D printer. Scientific advancements though might well require access to advanced laboratory facilities (although some might come about solely through mathematical techniques).
It's hard to provide a more detailed answer to your question though, as the subject is so broad. To become an inventor, you need either to be able to identify a need for something, and then find a way of satisfying that need, or to be able to find a new use for something that already exists.
To become a scientist, you almost certainly need a good understanding of advanced mathematics and the ability to find practical uses for it.