Easy way to make cakes look professional? ?

I think in this case you it really is a case of practice makes perfect.

The easiet way is to buy them at a bakery

The fondant should stick to the layer of frosting, Or you could coat the cake with apricot jam that has been heated so it thins out, [brush it on with a pastry brush] to stick the fondant on the cake instead of frosting.

It's called fondant not fondue. Seems you didnt watch enough videos. Fondant tastes like garbage anyway so just leave it off

as far as I know, you do NOT use fondue on a cake.

You are completely over thinking it. Skip the videos.

have you considered taking a cake decorating class at your local college? those are fun, and informative.

Nikki said it but I'll stress it. One of the biggest single factors is trimming the cake tops to straighten them up. Squared off top over squared off bottom makes a level, professional cake.

Spray then line your pans with parchment paper to make it easier and fool proof in removing the cake from the pan.

Then make sure you have the same amount of batter in each pan. Either weigh or measure it out.

When the cake is done, if there is a dome to the cake trip that off, easy to get it perfectly level if you do that using the pan as the cutting guide. Leave the cake in the pan and run a serrated knife across the top of the cake pan cutting off the high part.

Place the cake on your serving plate.

Measure out the frosting and spread it to the edge.

If you are going to use a filling other than frosting pipe a ring of frosting around the edge of the cake about 1 inch high. Put your filing in the center and spread it to the piped ring of frosting that will act like a dam.

Place the second cake layer on top and press down gently to seal the top and bottoms together.

Put a thin coating of frosting on the sides of the cake, this is called a crumb coat, it will seal in all the crumbs.

Place a thin layer on top as well.

If you are using Fondant apply it now, the crumb coat will allow the fondant to stick tot he cake.

If you are not using Fondant let the crumb coat dry a bit then apply a thicker layer of frosting.

Fondant. It's like wrapping paper, for your cake! Trim the top, sides and edges so they're even and neat. Apply the fondant and ice the seams.

Fondue on a cake, interesting.

https://en.m.wikipedia.org/wiki/Fondue