Step 3) Fancy fancy.
Think of how pleased your honey (relative, friend, whoever) will be when they see what you've done JUST FOR THEM! The ooh's and ahh's your creation will elicit from party guests, the pride you’ll feel when you’re finally finished. (I promise, no matter how many cakes you’ve made in your lifetime, you’ll always feel proud when you're done.) 

If you have no plans to decorate your cake, you’re done! Step back to look at your marvelous concoction, and beam with joy at your handiwork.

You may, however, want to get a bit more elaborate. You can add a little bit of texture by gently pulling the serrated edge of a long knife (that bread knife you used for trimming is good) over the top, after you've smoothed it out with the straight side. Pull it back and forth for waves. You can also make little spikes on the cake by tapping it with a small spatula, a butter knife, or the back of a spoon. This looks great on the sides.

If you'd like to write on your cake, do it first with a toothpick, which you can then easily trace over with a pastry bag. (If you don't have a pastry bag, get the stuff that comes in a tube from the grocery store, or use a sandwich bag. Just make sure it's the kind without pleated corners, fill it with icing, then cut off a tiny bit of the corner.) Decorative icing for writing can be made easily with just powdered sugar and a little milk or water. Start with 1/2 cup sugar, and add liquid 1 tsp. at a time, continuing until it's thick enough to hold it’s shape, but stopping before it gets pasty.

If you HAVE a pastry bag, by all means, add fancy borders and flowers. It's not too hard, but it does take some practice. Practice is crucial, and you can do it on a piece of waxed paper or foil, scraping up the practice attempts and putting the icing right back in the bag (it won't hurt it).