Paisley-Shaped Brows: A common tweezing mistake. Shaping the brow so that it has a round clump or hook at the inner end and then trails off narrowly never looks good.
Excessive Tweezing, Holes: Overaggressive tweezing will result in bare spots, or holes, in the line of the brow. Try to see where a hair falls and what the overall picture will be before tugging away.
Tattooing: I am totally against tattooing the brow; it never looks natural. It is much too extreme a measure.
Shaving: Even if you really hate your eyebrows, shaving them off is not the solution. With repeated shaving over the years, brows do not grow back fully or regularly.
No Maintenance: Every adult woman should do a basic brow cleanup no matter how natural her look.