All your dues must be settled. This includes, electricity bills, water bills, personal loans taken from banks, telephone bills, etc. Note that everything is linked to your iqama number, so a simple run of your iqama number by the passport authorities would easily point out if you are indebted to anyone.
Your traffic fines must have been paid and you must have no outstanding dues. This is one of the most serious issues affecting expatriates. You may have paid your dues, but you must make sure that it has been entered in the system. If not, you must personally go to the Passport Office with your sponsor along with proof of payment to get your name cleared. A simple way to verify if you have any dues or not is to just visit the Ministry of Interior's website and enter your iqama number. As the Ministry prohibits giving their website link, I am not giving the same here. But a simple Google search would lead you to the same. Another way is to just sms 88993 and type your iqama number. You will immediately get a reply about the status of your fines, if any.
You must close your bank account. This should be one of the last steps you should take, because it involves your final settlement from your sponsor. Take two letters from your sponsor. The similar letters, written in Arabic, should mention that you are going on final exit and that an 'X' amount has been transferred to your account which would be withdrawn and the account closed. Present one of these letters to your bank, which would only then allow you to close your account. In case you wish to transfer your money through SpeedCash or Western Union or any other bank, you must use the second letter in that office.
If you stay in a rented house, you must disclose your intentions to your house owner. If you are going mid-way through your house contract, it is advisable to fix any other expatriate to continue with the rest of your contract period, otherwise you will end up paying for the unused portion of your contract. Word of mouth is the fastest way to do this, but posting it in your nearby supermarket is also another common method.
In the unfortunate event that you have paid all your dues, but you inturn are to receive money from certain people, you should nominate your friend to get it on your behalf. There is no guarantee, though, that you will get your money, but if going out of the kingdom is your priority, then you have no other choice but to do this.
I would advise you to send your family out of the kingdom before you actually leave. Not that it is mandatory, but this is just to avoid their being put into trouble due to last minute surprises.
The bottom line is that there should be no financial dues from your side and that your name should be clear of all fines / any record with the statutory authorities, to get your final exit. Once your iqama is submitted, and all the above conditions have been fulfilled, it is only a matter of time before your passport is stamped with an exit visa. Usually, the passport is given to you in the airport just before you leave as the sponsor's responsibility is to make sure that you really leave the kingdom, but some companies also give the same to you a couple of days earlier. Good luck for your future!