Small Aircraft; Low Wing; 1 Eng; Retractable Gear
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 7; Flight Crew Total 2100; Flight Crew Type 990
Situational Awareness
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway; Ground Incursion Taxiway
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Human Factors
During taxi on an IFR flight plan; I was cleared to taxi Foxtrot to Sierra to [Runway] 12L at STL.  I had the taxi diagram displayed on the MFD of the G1000 and was using it for reference while taxiing.  I became fixated on Runway 12R on the taxi diagram and was mistakenly thinking I was taxiing to [Runway] 12L but in fact was heading towards [Runway]12R.  After the turn to taxiway Sierra; I informed Ground that I would need a 1 minute run-up prior to departure.  During this exchange; ATC asked what I was doing and when I looked back to the taxi diagram; I realized that I had just crossed the departure end of [Runway] 12L.  Ground asked me to taxi past [Runway] 12L and then stop; which I did.  I apologized for my mistake and asked ATC for further instructions and was instructed to do a 180 back towards [Runway] 12L and hold.I've flown into many Class B airports without an issue but feel that at least one contributing factor was my infrequent flying since COVID.  In a normal year; I fly 300+ hrs but in the past year have logged only ~60 hours.I spoke with my flight instructor and FAA examiner about the incident including factors that led to the incursion and thoughts about how to avoid repeating the incident in the future.
Light aircraft pilot reported a runway incursion during taxi and cited lack of current flying experience due to COVID restrictions as a contributing factor.