If you want to use "se no takai(hikui)", there has to be a noun after this or it is just a fragment. For example, "se no takai dansei", which means "a tall man". The expression "se ga takai(hikui) can be used by itself but more likely to be used with some noun before or after this so that it make more sense. For example, "se ga takai dansei", which means "a tall man" or " ano hito ha se ga takai", which means "That man is tall". Sorry for my poor English. Hope it is helpful.