GFK Controller described an error in release procedures. Varied and numerous indicators are described as becoming cumbersome and contribute to mistakes.

Narrative

Procedures at GFK require; during manual releases; a red indicator be in use at all positions stating HFR and that when IFR aircraft are taxied out for departure that Ground Control gives the IFR strip to the Flight Director position to get the IFR release from Approach Control; and that the strip not be placed at local control position until it has a release. Aircraft X was an IFR aircraft and the strip had been placed on my local control podium in a lineup of about six other departures. This was the first IFR departure that I had worked since I had been on local control. I had not looked at the IFR strip; other than to glance at the initial routing. I was thinking about a single engine VFR departure ahead of Aircraft X and that with the strong winds prevailing it would be best to turn the VFR aircraft early ahead of him for better separation. When Aircraft X called ready for departure; I checked the strip which had no release but failed to scan the podium to see the red HFR marker which was in place a few inches above the strip. I formulated a heading and spacing and cleared Aircraft X for takeoff on initial runway heading; then called Grand Forks Departure prior to Aircraft X starting to roll and called him active and gave them the formulated heading. Departure did not say anything about manual releases at the time and accepted the active call. Aircraft X departed and was turned to the appropriate heading; then transferred to Departure. Approximately five minutes after Aircraft X contacted Departure; Approach Control called and gave us automatic releases at which time I realized what had happened. We have many visual markers in use on our podiums now and they are becoming somewhat cluttering causing us to have to work around them and as they get in our way. The current red HFR marker is on a strip holder that contains the two departure runways and has a sliding blank that can be moved between HFR and RLSD to signify manual or automatic releases. Departures are placed with strips beneath this marker system. As other departures in line are taxied out; they are placed above the first in line and it separates them from the marker as it is currently used. The first aircraft in line being at the bottom and when we clear them for takeoff or taxi into position to hold we pull them down to the bottom of the podium. It may help to have a separate HFR marker to indicate when we have manual releases that should be placed at the bottom of the departure lineup; as we pull a strip down to the bottom when we clear them for takeoff; making it easier to see the strips next to each other. I will suggest this; however; space on the podium is limited and somewhat prohibitive of this as it would take up extra room on the podium. I will have to rearrange and improve my scanning habits to prevent this from happening again.