In regulating the amount of capacity, or inductance, or current in the A battery, you will at first be amazed at the great difference effected by a very slight adjustment. Some sets are equipped with micrometer adjustments, as the direct action of the hand will often turn the knobs too far. Bear in mind the importance of keeping all wires connecting your instruments as short as possible, particularly the wire leading to the grid. Avoid parallel wires, as far as you can, as the capacity between them may disturb your adjustments, and if your wires must cross each other, let them do so at right angles and keep them apart. A whole book could be written about tight connections.
Loose ones cause endless trouble.
Unless wires are securely and tightly clamped to their proper connections they should be soldered. Often a wire is properly fastened to a binding post but the post itself is loose in its base, or the wire on the under end of it is not properly screwed or soldered down. Make a habit of placing the end of a wire around a binding post or other screw from left to right, so that tightening the screw will not tend to throw the wire out of place. For the sake of neatness, you may wrap the ends of the insulation with tape to avoid fraying. Some insulation is made of two layers wound in opposite directions, in which case the ends may be tied in a knot and clipped short, so as to prevent further unwinding.