Употреблять is usually used for some products, drinks or medicine. употреблять=to сonsume E.g. Употреблять спиртные напитки = to drink alcohol. Употреблять в пищу = to eat Употреблять по 2 чайных ложки 3 раза в день. = To take 2 ts for 3 times a day. Использовать is about the exploitation of the things (to use): E.g. Использовать интернет = to use internet Использовать разум = to use one's intellegence Использовать карандаш = to use a pencil (Sorry for my poor explanation, I hope it helped you a bit)

"употреблять" is mostly used when you are talking about food/drinks/drugs/pills/tablets/ or when you say "я употребила это слово в данном значении" ="I used the word in this meaning" And "использовать" is mostly used when we talk about something that helped us doing something.

fridge or internet or anoter technical devices - always - использовать