Adwaita vs visishtadwaita philosophies

Adwaitam
In this philosophy, proposed by Sankaracharya, everything is "maya" or "brama". Just like the objects, animated or inanimated, in dream not real, so are the things that we see in our lives with out eyes. Then the "I" is not the "I" as we imagine with the body and soul. Even this could be a dream. What is not a dream and so real is brahmatvam. That is how Sankaracharya explained, by taking the words "tat tvam asi"..you are that or that is you. Everything else is maya. Even the person who is teaching this, vedas and all is maya.
But the problem with this is that the sentence is taken out of context and a literal translation is done instead of looking at what is said in vedas before that sentence and after that sentence. Another way to explain this using an example is to imagine a pot of water. Say to see the reflection of sky or sun in the water. When you shake the pot, it appears as if the sun or sky is moving but in reality it does not change. Even if the pot breaks and water spills and reflection of sky disappears, the real sky (brahman or brahma tatvam) remains. That is also called awareness or chaitanyam.

kunda(tvam)-sky(tat)
- just awareness (chaitanyam)
-jgnanam
-qualities themselves, no one has it

Visistadwaitam
This is not a philosophy proposed by anyone. What Ramanuja said was to take what is in the vedas and upanishads as a standard than studying them with a preconceived notion and then interpreting them and validating that preconceived notion. So he proposed to study all parts and see if it fits in to that standard mentioned in vedas.

When "tat tvam asi" is studied as a whole, and the part that is before that sentence and after that sentence is fully understood, one can see the context in which it is said.

If one were to explain this by an example, take a seed that is planted and grown to become a tree with leaves, fruits and branches. Same way, before we all and the universe was created, there is TAT that existed which we call "brahma tatvam" or "narayana tatvam". It is He that made a sankalpa to create the universe (just as a plant was born). All the objects are a part of Him and His creations. And He has the ability to create, control and destroy it so He has all the qualities.

seed(tat) - leaves, branches, frruits (tvam)
- not just awareness but someone with awareness (narayana with awareness)
-jgnanam kaligi vunnavaadu
- He has all qualities