There are several things you can do to take good care of your tent. But do not put it in the washing machine!
Set up the tent, and cover with a cloth or sponge and warm water. Do not use strong soaps and do not put the tent in the washing machine. Then you do more harm than good. Here there are no breathable membranes whose microscopic pores must be kept open. If it has become really muddy or sandy, it is still good to be able to dry, brush and shake most of it, so that fine-grained sand does not gnaw and wear on the fabric. If you use footprint, this tent protects against getting dirty. A footprint is also significantly easier to clean and helps to keep the tent dry - which will have a preventive effect against condensation and less need for drying after the trip.
A tent that is a water-repellent will, as a side effect, also is naturally dirt-repellent. Thus, there is rarely a need for particularly more cleaning of a tent than to brush off the debris and quickly that accumulates in the inner tent. A tent has a bit of the same non-stick properties against the dirt as the Teflon pan you have in the kitchen. If you rub and scrub with heavy soap and steel wool, you do more harm than good.
Cleaning the poles is extra important if you have used the tent a lot by the sea, for example on a paddle trip, as deposits can easily form on the connections between the poles, which means that they do not go together completely. Also, remember to wash the plugs if there is a lot of soil left on the plugs after use.