Basicly, you will never understand the difference between these things. Unless you know perfectly the words(or you're a native), you will not be able to differentiate these consonants in a conversation. It happened to me with 놓다 and 넣다. To my professor, the difference is evident and natural. To me, there is no difference in pronouncing these two verbs.

Hey there, I see that many people have difficulties pronouncing or differentiating the sounds between ㅈ/ㅉ/ㅊ, ㄱ/ㄲ/ㅋ and ㄷ/ㄸ/ㅌ. I think the simplest way of thinking is to look at what these korean alphabets are equivalent to the English sounds (which is obvious but effective)... but since it is still ambiguous I would break the sound into the following: ie ㅈ = J, ㅉ = JJ (almost like Tch) and ㅊ = Ch 자다 = Jada, 짜다 = Tchada and 차다 = Chada 잔디 = Jandi, 찜질방 = Tchimjillbang, 청소 = Cheongso Hope this helps!