Using words in sentences. special,white,possible, hard,marketable,skirt,low,recent, panicked,trust

Place spaces after your commas.

The special thing about this app is that it taught me how to use better grammar.

She gotta white complexion.

She has a white complexion.

You can also say 'she's got a white complexion'.

Everything is possible if you are confident on yourself.

Everything is possible if you are confident in yourself.

It seems quite hard to obey your orders.

This sentence also works fine if you remove the word 'your'.

We should see the marketable value of this place before buying it.

This one would be 'market value'. 

She bought a new grey skirt for the party.

If you’ll think about that incident you’ll feel more panicked.

If you think about that incident you'll feel more panicked.

I often feel low whenever I saw people stronger than me.

I often feel low whenever I see people stronger than me.

The recent discoveries showed that Copy numbers variation are the reason for most common diseases.

I am not sure what this sentence means, but you used the word 'recent' correctly.

Trust is the key to build relationships.

Trust is the key to building relationships.