One really must "follow the book" at least until one is comfortable with the plant and knows its tricks. Most beginners' probs arise with watering and fertilizing. Watering should be done only as needed and not by a set schedule and ferts should be used with caution and never at amounts listed on directions. Most ferts are made for outdoor gardens or houseplants and adjustments are needed to use them for cannabis. As long as fresh, quality potting soil is used there will be no need for adding any trace elements or anything beyond quality ferts and maybe a food/hormone additive such as "Dark Energy" or the like (and water of course). But in general, most problems are caused by the gardener giving their plants too much love and attention.