Low FICO score despite paying all credit cards on time, in full – help?

I am currently 25 years old with one major credit card that I have held for nearly 10 years. I carry a few store credit cards as well. I pay all of my credit card bills on time, in full, never carrying any outstanding balances on any cards. All car payments paid on time, no student loans left…I recently checked my credit score for mortgage purposes and it was mid 600s. I was also denied a major credit card application based on my current score. What can I do to improve my FICO score??
I am currently 25 years old with one major credit card that I have held for nearly 10 years. I carry a few store credit cards as well. I pay all of my credit card bills on time, in full, never carrying any outstanding balances on any cards. All car payments paid on time, no student loans left…I recently checked my credit score for mortgage purposes and it was mid 600s. I was also denied a major credit card application based on my current score. What can I do to improve my FICO score??

In reply to comments – score pulled by bank for mortgage purposes, showed scores from all 3 major agencies. Read through the credit report fully, no red flags. I can’t figure out what pushed it down unless perhaps I just haven’t built it up enough?
Also, no changes in my credit limit.

Getting a home loan with low credit score?

My aunt has owned a home for the last 10 years, just
recently she was in a very bad situation where she got
behind on her mortgage. She is now caught up and in
good standing but her credit check doesn’t show this.
How long until it shows up and how soon will her credit
score begin to increase? Al

Getting a home loan with low credit score?

My aunt has owned a home for the last 10 years, just
recently she was in a very bad situation where she got
behind on her mortgage. She is now caught up and in
good standing but her credit check doesn’t show this.
How long until it shows up and how soon will her credit
score begin to increase? Also her score is very low
around 550. Is there any chance she would be able
to get a new home loan? We are trying to get her into
a smaller home. Thanks