I always use suddenly when to create a surprise moment to my characters. For example: The hunter walked silently through the bush to Suddenly, the leopard jumped from the tree and pounced the hunter. What examples can be the best way to write surprises in fiction without sounding too telly?
Suddenly is an unnecessary word. If it was quick and unexpected, it is a sudden surprise. So, just lead up to it well. Example: The hunter walked through the bush. The leaves crunched beneath his feet, the birds chirped high above. He didn't hear the leaves crumbling behind him, he didn't sense its approach, but before he knew what had hit him a leopard had pounced and tore his throat from his neck. Alternatively you could skip the lead in and go with: The hunter searched for his dinner not knowing a leopard was poised above him licking his chops. One of them had dinner that night, the other was dinner that night. The hunter died hungry and shocked and in pain. If you use suddenly you have squeezed the shock out of what of what you're about to say. For instance, if you say to someone 'Suddenly, I don't like you very much'. It almost softens it. The other person prepares for the shock and so it doesn't hit as hard. Whereas if you say 'I don't like you very much' when someone thinks you do, then that will be a shock. Hope all of this makes a little bit of sense.
I agree with @Who , using 'suddenly' helps the reader know that something unexpected is about to happen, which ruins the surprise of the unexpected thing. It's counterproductive to what you want to do: surprise the reader. Here's an example: After a moment of struggle, Joel fell over the railing and onto a metal spike which tore through his chest is a lot more sudden, horrifying and shocking than, Suddenly, after a moment of struggle, Joel fell over the railing and onto a metal spike which tore through his chest. Which sentence looks like it would surprise the reader more? The sentence where they didn't know that anything different would happen, or the sentence that prepares them? Don't do what J.K. Rowling did when Harry and Cedric arrived at the graveyard in Goblet of Fire. She wrote, and I quote, "Suddenly, without warning, Harry's scar exploded in pain." Thanks for the warning that something without warning was going to happen, ma'am.
So you just write the surprise in the middle of the sentence as you write the description. It does sound better without suddenly.