There are so many techniques and trends that are sweeping Instagram, Snapchat and beauty blogs when it comes to filling in brows that it can be difficult to choose what will work best for you. The first thing you want to do is make sure that you have the you achieve the desired look is by having your brows professionally shaped.
Secondly, you want to choose the brow product that best suits your skin needs and lifestyle needs. If you go with a pencil be mindful of the coal soft textures – these tend to run and smear on oilier skin. If you decide to choose powder be mindful of the process itself. With powders you need an angled brush along with a mascara wand to comb and soften the powder once applied. Brow gels and mascaras work best for brows that are fuller, but it can be difficult getting the color from these products to stay in place. Brow pomades I don't particularly recommend as the product itself can be comedogenic which can stagnate growth.
My favorite style of product to use is powder, and my application is as follows: outline the bottom of the brow with a defined line, use the mascara wand to brush brows upward from you line softening the line and blending the color. Outline the top of the brow with a less defined line than the bottom and stroke your brush throughout your brow from front to end using more product at the tail to make it more defined.
Keep in mind your brow length and your daily routines when selecting what color fill in technique will work best for you. I find powders to be the most versatile, but I encourage clients to branch out and try various methods to achieve the look that works best for them.