When you learn about classic cuisines you notice that the original recipes dont have amounts or much instruction in them. Ingredients may have been measured but they were not recorded in the recipes because the cook was expected to be able to understand and work it out for themselves.
A good example is a thai curry paste: each ingredient is added to the pestle & mortar separately until the aroma balances the previous ingredient (which are added in opposites, chilli then lemongrass for example). People started to write comprehensive recipes so we could shortcut the experience & learning needed for this task. Now we have standardized recipes but they dont take into account the differences occuring in nature. Ingredients vary dramatically and modern recipes have now forgotten to mention this. Then the food processor arrived (which shreads and doesnt pound like the pestle) and the result changes again. The difference is obvious when written out like this but in a recipe they would be identical.
This is an example of why you need to be discerning in who you learn from (i.e. dont just trust google to come up with a recipe) and how keenly you learn/get involved. Recipes should be like essays basically! With regard to BIR you need to understand the ingredients and how they work, which is no small feat. You need to be constantly smelling/tasting so you get used to the differences that occur each time you do something. I find i often have to do control experiments to work things out. When you taste you need to be discerning rather than accepting. You need to try and criticize every aspect of the food in your mouth. Check there is enough salt to bring out the flavours (and spices need salt as much as anything else, dont listen to the health experts), that the sweetness is correct and that the overall 'feel' in the mouth is correct. I'm sure most of you have tried making multiple base sauces and found shortcomings in all of them. All you need to do is keep tasting them to work out what is wrong with them. Be the critic. The presence of onions which havent been completely cooked is the most common IMO so you'll probably recognize that 'vegetable sharpness' already. If you keep on with the other ingredients, even smelling a piece of ginger between tastes of the sauce to help you notice a subtle spicy edge to the aroma which you previously thought was to do with the ground spices, you'll be on the right track.
This way you'll find that with most recipes you will actually do them slightly differently to how they are written down, and might need to make adjustments each time. Dont let this deter you or make you think the recipe isnt perfect as this is how the professionals do it. They taste each dish & each sauce before it is served.