He provides for preventing the enemy's knowing on which side his attack is to fall; instead of engaging an equal number of their ships he provides for breaking their line, and engaging the bulk of their fleet with a superior number of his own; and finally he looks to being ready to contain the enemy's rear before it can do him any damage.
Thus, taking together the general order of 1798 and the Toulon memorandum of 1803, we can see all the tactical ideas that were involved at Trafalgar already in his mind, and we are in a position to appreciate the process of thought by which he gradually evolved the sublimely simple attack that welded them together, and brought them all into play without complication or risk of mistake.

This process, which crowns Nelson's reputation as the greatest naval tactician of all time, we must now follow in detail.
Shortly before he left England for the last time, he communicated to Keats, of the Superb, a full explanation of his views as they then existed in his mind, and Keats has preserved it in the following paper which Nicolas printed.
'Memorandum of a conversation between Lord Nelson and Admiral Sir Richard Keats, the last time he was in England before the battle of Trafalgar.[11] 'One morning, walking with Lord Nelson in the grounds of Merton, talking on naval matters, he said to me, "No day can be long enough to arrange a couple of fleets and fight a decisive battle according to the old system.

When _we_ meet them" (I was to have been with him), "for meet them we shall, I'll tell you how I shall fight them.

I shall form the fleet into three divisions in three lines; one division shall be composed of twelve or fourteen of the fastest two-decked ships, which I shall keep always to windward or in a situation of advantage, and I shall put them under an officer who, I am sure, will employ them in the manner I wish, if possible.

I consider it will always be in my power to throw them into battle in any part I choose; but if circumstances prevent their being carried against the enemy where I desire, I shall feel certain he will employ them effectually and perhaps in a more advantageous manner than if he could have followed my orders" (he never mentioned or gave any hint by which I could understand who it was he intended for this distinguished service).[12] He continued, "With the remaining part of the fleet, formed in two lines, I shall go at them at once if I can, about one third of their line from their leading ship." He then said, "What do you think of it ?" Such a question I felt required consideration.