Just to be sure, check that the Estate Disposition bars in the Overview tab are all at 100% (for example, all debts resolved). If any heirs have been specified for a specific percent of estate distribution, ensure those heirs' distribution percents match their targets in Heir Target Allocations chart at the bottom of the tab.
Since tax agencies can sometimes review your submissions and decide that you owe additional amounts, it's good practice to keep some cash in reserve for such contingencies. You can still make the bulk of the estate distributions in the meantime (as long as you're reasonably sure of the situation).
Note that if you had to file a federal Form 706 and/or its associated state forms, you will also need to receive tax clearance letters from the agencies with which you filed, stating that there are no outstanding tax issues ... and this can take 6-9 months from when you submit the return (fortunately only a small percentage of estates are large enough to require a Form 706).
See Paying Taxes for a reminder of decedent and estate tax reporting obligations.
Trusts terminate when the defined termination date or event occurs, such as the death of a beneficiary or the date the beneficiary attains a stated age. If you are the executor of an estate, and the trustee for an associated trust, you do not have to wait for the trust to terminate before closing the estate.
If the estate has gone through an official probate process, you must submit (and get approved) a "Final Accounting", which shows how you handled the estate assets: what income the estate generated, what losses, how much you paid the individual creditors, and how much you distributed to heirs.
If the estate has gone through an official probate process, the last step is to submit (and get approved) a "Closing Statement", stating that you have resolved all debts, paid all taxes dues, and distributed the estate net proceeds appropriately.
By this time, there really shouldn't be anything left in the estate, other than perhaps the estate bank account you opened. You probably closed this account when you distributed the proceeds, but if not, now's the time.
If you filed a Form 56 with the IRS when you became an executor (or at any time), you should now file a corresponding Form 56, notifying the IRS of the termination of your responsibilities.