Sounds like you are doing alot right, and working well with your wife to manage the anchoring process. A kellet is a weight that you attach on a separate line, and then shackle to your anchor line/rode, and slide down part way. The purpose of the kellet is to weigh down the anchor rode so that it lays more horizontally than it would without the kellet. The basic principle is that you want your anchor line at the base to lay flat on the ocean floor (preferably with chain at that point to avoid chafe). This is helped by having heavier chain there, having the kellet weigh down the rode, and having enough rode/line out. The purpose of all of this is to keep the anchor pulling horizontally to remain stuck, rather than vertically to dislodge. The weight of the kellet and chain also absorbs some of the shock/pull from wind and waves in rougher conditions.
Finally, you can buy a kellet, or make your own once you understand the principle.
Hope that helps. Comments from others welcome as well.