GA pilot reported having difficulty locating the arrival airport resulting in disorientation and a descent towards terrain; the pilot regain orientation and landed safely at the airport.

Narrative

While approaching ZZZ for landing I had difficulty finding the airport and that distraction resulted in my descent to a lower altitude than intended. Although I had been to this airport before it had been some time. The primary cause was my lack of pre-flight planning; knowing this airport is difficult to discern in the dense urban area in which it is located; I should have had a pilotage plan. In the past I have used a major freeway and known buildings to identify an approach path to the airport. In this instance I merely used a GPS direct course from my departure airport; ZZZ1; to ZZZ since the flight was so short (8 minutes). This resulted in an unfamiliar sight picture vs previous flights to ZZZ resulting in disorientation; distraction; and the result was an altitude deviation.Corrective action is to properly plan ALL flights; even brief ones in perfect weather!Secondarily; paying more attention to having the aircraft properly trimmed would have prevented the descent.