Like --> Like is used as a preposition and should be followed by a noun
Ex.: "It's hot in this room. It's like an oven!" - Both an oven and this room are hot
Ex.: "She works in a hotel, like me." - We both work in a hotel.
As --> As is used to compare something that is the same as something else, or in the same condition. Use a subject and a verb after as.
Ex.: "As I told you, the meeting started at 3pm."
Ex.: "It rained all weekend as we thought it would."