Air carrier First Officer reported FLL taxiway signage is confusing and could be improved.

Narrative

The incident occurred taxing out to Runway 28R from our gate for takeoff at FLL (Ramp Control). During pre-flight planning the crew discussed the full sequence of events for the flight and noted that the aircraft was not parked in one of the primary gates listed on the company pages. As a result; considering the proximity of the runway to the gate the crew agreed it would be best to start both engines for taxi. This was again mentioned during the 'Threats' portion of the brief and discussed by the crew that we would complete the 'Before Takeoff' checklist prior to leaving the ramp as a mitigation - in this case due to both the proximity to the runway and there seemed to be very few aircraft operating at the time leading to an expectation there would be no delays for departure.Everything from the brief through the 'Before Push' checklist was uneventful. Once ready; the FO called Ramp Control for push from the gate and received clearance for 'Spot 0.' This spot is not displayed on either the Jeppsen 10-9 Chart or company taxi page; but was quickly located by the crew on the 10-9B page. The Captain relayed the clearance to ground handling personnel and the aircraft was pushed back uneventfully. As briefed; both engines were started and the 'After Start' checklist was completed. The 'Before Takeoff' checklist was started and the Captain observed some ground vehicles and ground personnel waiting for us to move; so we stopped the checklist and called Ramp Control requesting to move forward and allow all of those waiting to be released. Ramp instructed us to 'proceed on Taxiway Bravo and hold short of [Taxiway] B12' - this clearance was read back as instructed. The FO and Captain subsequently cleared our respective sides of the aircraft and commenced an immediate left turn onto; as it later became apparent; Taxiway Tango holding short of [Taxiway] B12. Based on debrief discussion; both the Captain and FO stated that we believed we were correctly following directions and we completed the 'Before Takeoff' checklist (including 'Final Items'); thereby leading to the FO going heads down once established on the taxiway.Based on our proximity to the runway and ATIS information stating 'FLL Tower' and 'FLL Ground' operations were conducted on frequency 119.3; we checked in initially with FLL Tower and we were instructed to switch back to FLL Ground on 121.4 (a new ATIS had just became active re-establishing separation of frequencies). As we checked in with FLL Ground we were instructed to 'taxi via Taxiway Bravo to Runway 28R.' The FO switched back to the company taxi page from the 10-9B page on Jeppesen and realized we were on Taxiway Tango - immediately reporting the error to the Captain. We agreed on the error and then reported our position to FLL Ground and requested a switch back to Ramp in order to correct the issue. Upon checking in with Ramp we were instructed to 'proceed on Taxiway Tango to T2; then switch back to FLL Ground' - all remaining operations occurred without incident.During debrief the FO and Captain recounted the sequence of events and noted that we both observed the taxiway sign ahead of 'Spot 0;' perceiving that it depicted Taxiway Bravo as being immediately to our left. Neither the Captain or FO recalled any sign for Taxiway Tango at that position. Reviewing each Jeppesen depiction it is clear that we needed to taxi straight ahead before making the left turn from 'Spot 0' - based on our perception at the time when calling for taxi this did not seem as apparent using visual cues.