1. In the Pulpit
Here the preacher places the limited notes on the pulpit. When done well, the audience may not even recognize or remember that the notes are up there. However it can be a disaster when done poorly. The other day I saw a preacher who would look at his notes, leave the pulpit say a few words, walk back look at his notes, leave again. It became completely obvious that the preacher either didn't know his manuscript or he does not have the gift to preach with limited notes. Wherever you keep your notes, you must know them well.
Some preachers are very good at making you think that they are reading the Bible, but they are glancing at their notes. Some are very poor at it. If you can't pull it off, put your notes in the pulpit.
3. In PowerPoint on Your Screen
A lot of churches have screen's now. They put up scriptures, hymns, and other things. You can easily put your main points up there and read very naturally your point. This is actually a very effective way to "cheat."
4. In Your mind
Here the preacher memorizes the notes. It is easier to be natural in this approach, but it also requires much more time to become familiar with the material.
Wherever you keep your notes, the best sermons are those that the preacher is very aware and knowledgeable of his/her notes and does not require too much reference to them. So whether you read, follow an outline, or go up without any notes, it is best to know your notes, wherever you put them.