Learn Fundamentally

 Fundamental knowledge means that you've learned a subject in a classical way, in the right order, with no gaps.

For example, if you learn fundamentally about organic chemistry, you
1. learn the topics in the classical sequence:
 alkanes, alkenes, alkynes; and then add functional groups: alcohols, aldehydes, ketones, acids, ethers, esters, amines, amides, proteins, and sugars.

2. understand the main concepts:
nucleophile, electrophile, dative bond, Lewis structure, VSEPR Valence shell electron pair repulsion, etc.

With fundamental knowledge you have a good foundation to build on, and you can understand specialists, have a common language with the scientists.

Here are a few of excellent channels to explore and build Your knowledge fundamentally on each topic:

1 - Organic chemistry - 30 videos sequence, free
Organic Chemistry Exam 1 Review - YouTube

2 - General Chemistry - all the elements in the periodic table by groups:
Periodic Table Part 2: Alkali Metals (Li, Na, K, Rb, Cs, Fr)

 3 - Perfumery and fragrances
1 - Molecules

4 - Electronics
Basic Electronics For Beginners

5 - Math
Evaluating Functions and Solving Basic Equations - Algebra - SAT Math Part 1

6 - Inorganic chemistry
Organometallic Reactions Part 1: Ligand Substitution and the Trans Effect - YouTube

7 - General chemistry
1.1. Алканы: Строение, номенклатура, изомерия. Подготовка к ЕГЭ по химии - YouTube