Welcome, @Anonymous. 
There are three ingredients involved with the revolving portion of one's score:
- Overall utilization
- Individual card utilization
- Number/percentage of cards reporting positive balances
The good news is that overall utilization is the most important, and all plans of attack will address it similarly. Individual card utilization is determined by the card with the highest utilization.
The ideal situation for number/percentage of cards with positive balances is to have positive balances on less than half of your cards. Some say that less than a third is better. Other than the fact that a single maxed out card will clobber your score, it's unclear whether individual card utilization or number/percentage of cards reporting balances is more significant.
Note that "under 30%" actually means 28.9% or below. That's because 29.000000001% rounds up to 30, and you'll no longer be "under 30%." If under 30% is a goal and you're paying interest, you'll want to pay down balances to 25% or so to keep the next month's interest charge from bringing you over 28.9%.
General advice to start with is to bring all card balances down to the 85% range. That should keep them below 88.9%, which is considered maxed. For us to give you suggestions beyond that, it'd be helpful if you'd list your cards, their balances, and their limits. That way, we'd be in a better position to determine if it's more practical to bring some balances to zero or to attack your cards relatively equally.
@Anonymouswrote:I have 10 credit cards with $30K available credit. I currently owe $12K on all the cards combined, which puts me at 37% total usage. I have the ability to pay down my cards by $5000, but I am not sure the best way to utilize the funds, but I would like to do whatever improves my FICO score the most. Should I:
1. Pay off cards lowest balance to highest balance?
2. Pay off cards from highest balance to lowest balance?
3. Pay off cards with highest APR and work down to those with lowest APR?4. Pay something down on all the cards?
One creditor told me it's okay to carry a balance on all cards, as long as I'm below 30% total usage. Another credit told me it's better if some of the cards have a $0 balance while carrying my total usage on the other 5 cards.
Thank you all for any suggestions you can make.
Items 1, 2, and 3 have to do with getting out of debt but have nothing to do with score improvement.
In order to advise you on score improvement we'd need to know the limits and balances on all your cards.
@Anonymouswrote:
For the purposes of this exercies, you cannot combine your cards and his cards together. You each have your own credit report and your own credit scores, not combined reports/scores. If your goal is to raise your scores, you need to list just the accounts associated with your report. If the goal is to raise both of your scores, you'd have to list out the accounts present on your report and then his report, as you both would have different accounts to target/tackle in order to see the best score increases.
Yeah, we can come up with what it would take to bring balances down below 28.9% (or as I mentioned, a bit below that for a safety valve). But we can't consider the number/percentage of accounts reporting positive balances without separating the cards.
@Anonymous, how flexible is your budget? You've mentioned a couple of different payment amounts. We don't know if those numbers amount to money you can pay right now or if you're just looking for some examples.
As I mentioned, I like the idea of getting accounts safely below 28.9%, e.g. 24–25%. I used 27% above because it appears that you can do that with not much more than the 10K you mentioned. I think it'd be more like 13–14K to get into the 24–25% range.
With the information at hand, I think a reasonable step one would be to get all accounts safely below 28.9%. Step two would be to keep them there and to start knocking off the lowest balances. With more info, a different plan of attack might look better.