Gosh that sounds like my constant preaching/harpingClimb a few feet above the ground (like on a picnic table) and throw your completed model a few times without power, just to see how it glides and ajust the trims as much as possible BEFORE commiting to your maiden flight.
If trimmed correctly (and with the C.G. in the right place) it should glide with no control inputs. If not, ajust some more.
The first flight is often so much harder than the 3th or 4th would be, simply because the trims are usually totally off.
That's why the best way (when possible) is having an experienced pilot for the maiden, who than passes you the remote.
Good luck! Keep us posted.