I posted these on another cake board, but thought they might be useful here.
Standard Mixing Instructions
You would sift all the dry ingredients, which means the flour, salt, baking powder and also spices, or cocoa powder and baking soda, cream of tartar - those would also be included, so sift them together in a separate bowl. Sugar is not considered generally as a dry ingredient, for mixing purposes . Now some people just stir the ingredients together, but generally you will get a better blend and get rid of any lumps, get the granular sizes of the various dry ingredients to a more consistant size so that they are better incorporated.
Then you take your fat ingredient, the butter, or shortening, well you mix this on low speed in a separate bowl (this will almost always be the bowl where all of the ingredients end up in), using the wire whip attachment. Once it is well creamed, you add the sugar gradually and mix on low until light and fluffy. If a recipe includes brown sugar, this would be added at this time. Then you add your flavourings, in this case vanilla and mix on low. Then you add your eggs and mix on low. Sometimes you want to mix each egg in separately, but usually this is not necessary. The only exception would be with an all egg white cake, which generally you beat the egg whites separately on high until stiff but not dry and then fold them in to the rest of the batter, by hand using a spatula.
Anyway you mix until the eggs are well incorporated. Then you add about 1/3 of your flour mixture and mix well on low. Then add 1/3 of the milk or liquid in the case of another cake recipe. Continue adding in thirds until all ingredients are well incorporated, you may mix for a few seconds on medium. Generally, unless a cake recipe states to do so, you are mixing on low to medium, not high as this incorporates too much air.
Generally you grease and flour your pans for all cakes with the exception of angel food cake types which you pour directly into an ungreased cake pan. To cool these cakes, they must be inverted, over a heat proof funnel or a wine bottle, until completely cool, then you use a knife to loosen the sides and rap the bottom of the pan to get the cake out.

Recipe Using Oil, Muffin or Sweet Loaf Recipes
If the recipe has oil, like Crisco oil or corn oil as the fat ingredient, well the mixing method changes. In those case, generally you stir all of your dry ingredients together in a bowl. Then you make a well or hole or indentation in the centre of the dry ingredients. Then you place your oil, sugar, eggs and any other liquid ingredients like your vanilla, in the centre of the well. Then you mix on low to low medium, just until ingredeints are incorporated, do not over mix. This is because generally this type of recipe makes a more muffin or loaf kind of texture and by overbeating it you will make the cake tough or rubbery.

Cooling
Well, generally, the larger the pan, the longer you cool the cake in the pan before removing, so the 5- 10 minutes is not always enough. I wait at least 15 minutes with all cake pans before removing the cake from the pan and up to 20-25 minutes for the largest ones. Then you flip them out and flip them again so that the crown side is up, if you are going to level your cakes. You are best off cooling them on cooling racks that you elevate to insure that the bottoms of the cakes are allowed to release the steam.

Cake Mix Instructions
Well, you are almost always best off following package directions. I do find that with certain brands, like Betty Crocker, you should also stir out the lumps or sift the mix or take a whisk to it, as I find this brand of mix particularily lumpy. Generally with cake mixes, if you are adding pudding mix, you stir this into the dry mix. Then you make a well or indentation in the centre and pour in your eggs, sour cream if you are using it, any additional flavourings and your liquid oil and other liquid ingredients. Then you mix on low until blended and continue mixing, usually on low to low-medium or medium for a couple of minutes or as stated on the box. Remember to scrape down the sides of the bowl and the bottom and always use the wire whip attachent, not the paddle, for mixing cakes. At this point if you are adding chocolate chips or raisins or something like this, you fold these in well using a wooden spoon or your spatula. Dipping these in flour will generally not stop them from sinking, it has more to do with the texture or weight of the batter in relationship to the additional ingredient, than the flour coating these things and stopping them from sinking.

Thanks for posting this for all of us ! Coating add-ins with flour hardly ever works for me. Glad it's not something I was doing wrong! My lil goodies just sink to the bottom unless I'm making a really dense cake like banana nut or chocolate-chip with sour cream and pudding.

Thanks for the information squirrelly cakes. You are a gem!

You are very welcome!
Haha Lisa, you are exactly right, the density of the batter in relationship to the density of whatever you are adding to it, is the big factor. Unfortunately, in my case, the density of the baker, doesn't help, haha!
Mixing methods are an interesting thing, now generally in a well written cookbook, you just follow the method given as there is a reason for it. But so many people get recipes with no methods attached. Sometimes, how you mix something isn't too much of an issue, but it really can make a huge difference in some recipes. Most particularly, the ones that tell you to beat the egg whites separately and then fold them in by hand. IF you just whip them in with the rest of the ingredients, well they will not produce the same texture.
Hugs Squirrelly Cakes