too much too little too late

how much is too much? Water air light. Since symptoms often look the same for over watering and under watering. Too much nutes or not enough. Lights too close or too far away healthy roots and brown roots. Keeping everything in a balance is a total mind fuck. When growing in 3 gallon pots with coco and perlite mix. I am having troubles dialing in and being consistent with the moisture content of the coco and nutes. I know all plants and rooms are different but it seems like I lean towards overdoing every thing including over thinking. Anyone can pull a lb. a light but I cant seem to consistanly do better. Its noticed in second month of flowering when bud swelling is taking place. I can tell by then if its going to do well or not. Any advise?

I tend to go on the light side of things as it is much easier to add water or nutes than it is to remove them.