If your iron is a regular steam iron I suggest you empty your iron when not is use so water is not sitting in the chamber. Distilled water is recommended, failing that cooled water from a boiled kettle.
Make sure your iron is on the steam setting and hot before you place it on your fabric because if it is not up to temperature it might 'dump' brown water onto your fabric. This is because it has not heated enough to turn the water into steam. I do not buy irons that switch off when not in motion for this reason.
You can buy a product to clean your iron internally (de-scaler such as Oust) and a you can also use distilled vinegar for the same purpose.
The sole plate of the iron should also be cleaned from time to time, either with a product made for this purpose or, as I do, using a nylon pan scrub moistened with a little water. Gently clean the sole plate with this when the iron is switched off and cold.
These steps done at intervals should keep things working well.
I personally cannot manage without a steam iron (and I use a spritzer too). Happy and successful pressing!