Here is what I gathered so far, please help correct this or add more examples and exceptions - thanks!
Verbs ending in -ам → (trivially) ам-conjugation
Example: пътувам/пътуваш
Verbs ending in -ча, -ша, -жа → it depends, needs to be learnt case by case
Examples:
пиша/пишеш; реша/решеш; реша/решиш
разкажа/разкажеш; лежа/лежиш;
оплача/оплачеш; окича/окичиш
Other verbs ending in -а → е-conjugation
Examples: чета/четеш
Verbs ending in -я →
If я is preceded by a consonant or “o” → и-conjugation
Examples: броя/броиш; правя/правиш
Exception: къпя/къпеш
Else → e-conjugation
Examples: пия/пиеш; живея/живееш