for a horror story always make the character in first person so for example "as i ran my heart skipped a beat i knew someone was following me but who and why" and usually because these are creepy make them have a creepy background "running through the spider webs and into the darkness i didn't care if i had spiders in my hair i didn't care if i was wondering around endlessly" always have the character contemplate what's happening "was this the end will have life stopped for the better of it is it time for me to be swallowed into the abyss"(i hope this helped)