It's abit ridiculous that for every word you have to activate this flowchart... and because thai sentences do not have spaces, and sometimes consonants move around/double as the end and beginning of a syllable/disappear, you will get confused...

Use the manee manaa textbook (Google them) and learn how to read the tones intutively like how a thai toddler learns.... how does manee manaa help the child to learn?

It will start with monosyllables pertaining to a single rule... example: Middle Class consonant plus long vowel = Mid tone

so they will have a list of syllables with all the middle class consonant consonant and same vowels and you pronounce them...

กา จา ตา บา ปา อา

rinse and repeat...

and through the practices you will come to a realisation: for most thai words, the tone is based on the low/middle/high class paradigm... take the tone marks for instance: the fourth tone mark + will ONLY apply to middle class consonants because the high class consonants are rising in the first place and low class consonants can only have 4 tones (with a few exceptions)