The first thing before you trim your eyebrow hair is to wax or pluck the unwanted hair around the actual shape of your eyebrows. Make sure that you are sitting in front of a clean mirror with some decent bright lighting. This will help you see all the little eyebrow hair easily. Make sure to take your time and be careful while plucking your eyebrows. Remember to not overdo it as you will want to create the perfect balance between both eyebrows. Make sure whatever you do to one eyebrow you follow the sample plan with the other one so it does not look awkward when you are finished.
The next thing is to brush them upwards so that you can analyze how you have to trim. Use your eyebrow brush to help you with this step. Be gently when brushing upwards.
Take some manicure scissors and carefully follow the shape. Try cutting small length of hair so that you can avoid any sort of mishap. Remember to be careful while using manicure scissors near your eyes. Always close the eyelid of the eye that your trimming over for safety reasons. Do not rush this step and take your time so that you can create a nice balanced look to your eyebrows.
After cutting again brush your eyebrows upwards and see if the length is properly trimmed. You will be looking to make sure that each small hair is perfectly trimmed and even. This goes for both eyebrows as you want a uniform look.
In the end brush the eyebrows in the normal way and with the help of a black eye pencil fill in the gap if you have any in your eyebrows. Try to avoid using too much eye pencil on your eyebrows as this can look awkward especially in the sunlight as it can be rather prominent in colour as compared to your eyebrow hair.