Most students who have studied English know the word “adjective”.  An adjective is a word that describes a noun.  These words can be related to the size, color, shape, or quality of different things.  For example, big, small, sharp, tall, hot, stupid, are all adjectives.  These words are easy to use, but sometimes they aren’t interesting enough to make a great sentence.  In many cases, we want to show that the adjectives have some affect on us, or on a situation. 
For example, sometimes we have to make an adjective seem more intense or remarkable.  To do this, we can use the word really or so.  When you want to describe an object and make the quality more important, you can say something like “Wow, it’s really hot today” or “That guy is really handsome”.  Make sure to give extra stress to the word “really” in this case.  This shows that the level of “hotness” or “handsomeness” is curious or unusual, rather than just an expected level.  Americans especially use “really” quite frequently.  Remember to emphasize it with your voice.  Because “really” is remarkable, the stress and voice energy should also be remarkable.  Don’t be shy! 
The word “so” is similar, but usually we use it to introduce a consequence or a problem.  For example, “I don’t want to go out today, because it’s so hot”.  Another example would be “I am so tired of studying.  I’m going to a movie!”  Again, we use stress and extra energy on the word “so” to show that we are intensifying the adjective. 
One of the most common mistakes that Korean speakers make is to use the word “too” instead of “so”.  What’s the difference?  We use “too” when we want to show that the quality is more than we want or need.  For example “I can’t study because I’m too tired.”  In this case, my level of being tired causes me to not be able to study.  “Too” highlights the adjective as being a negative or unwanted circumstance.  Just like “really” and “so”, this word should have noticeable stress and energy. 
So, as you can see, these words are really useful.  They are so easy to use; all you have to do is practice.  It’s not too hard - just keep working at it!