Here is a glimpse of my credit history:
First Credit Card opened: 2010 (now closed).
Number of revolving credit cards: 6 + 1(charge card)
Number of inquires in the past 12 months: 11 (mostly from several car loan applications).
Over the past year I always carried a balance and ran very very close to the credit limit - but then a month ago I paid down most of my credit cards and I got my utilization from 90% down to 29%. My FICO score went from 600 to 644. But this is still VERY low to creditors .. I have been wanting to get out of the small limit cards and apply for some high level credit cards .. but my hopes hit a huge wall. Chase denied me for the CPS and AMEX denied my 3x CLI.
I just have no idea how to get my score high enough for approvals to come .. I am not seeking more cards. I just want better limits on my cards .. they are all stuck at or below $1500.
Any advice is appreciated.
Would suggest listing your cards, when you opened them, any other tradelines (installment?) and whatever derogs you have.
Also whatever remaining balances you do have though you've been around long enough that you probably know the standard advice for optimizing your credit card reporting 
.
I have these cards:
Chase Freedom - $1500 CL - opened 5/2012 - Current balance: $300
Chase Amazon - $1500 CL - opened 7/2012 Current Balance: $350
Discover - $1000 CL - opened 8/2012 (recently asked for a CLI from $500). Current Balance $0.
AMEX BCE - $1000 opened 5/2012 - Current Balance $350
AMEX Gold Premier - opened 5/2013 Current Balance $250
Barclay's opened 9/2012 - CL $1000- Current Balance: $900 (the only card close to CL).
I have recently been approved for a lease with Audi - not showing my CR yet. I have an installment loan from 3 years ago with perfect payment history (only reporting with TransUnion).
I had a car loan two years ago with a 30-day late.
My TransUnion score seems to be the highest .. Experian score is moving up very slowly.