There's a real limit to what's safe to do without a professional here, and it's worth being straight about it. Lubricating hinges, rollers, and the track with the right garage door lubricant, checking that the door reverses when it hits an obstruction, and visually inspecting cables for fraying are all reasonable for an owner to handle. Adjusting spring tension is not. Torsion springs on a door built in this era are wound under load that can cause serious injury if the winding bars slip, and we don't recommend an owner attempt that regardless of how straightforward it looks in a video. Balance testing, disconnect the opener, lift the door halfway by hand, see if it holds, is also fine to try yourself, and it's one of the best early warnings you can get for a spring that's losing strength. If it doesn't hold position, that's the point to call rather than keep working the door manually.