Is there a word for announcing someone's arrival, kind of like a prelude for something or someone important?
What do you think of the verb to herald? It sounds like this one is exactly the word you're looking for. Here's how the Macmillan English Dictionary defines it:
(mainly literary) to announce something, or to be a sign that something is going to happen soon
The recent discovery of large deposits of gold is heralding a new era of prosperity in the region.
The thesaurus has:
Definition: declare arrival Synonyms: predict, indicate, signal, harbinger, signify, forecast, herald, forebode, foretell, augur, portend, presage, foreshow, forerun
... All x of which have the problem that "i xed" or "i was xed" not neccessarily means " i announced my arrival" or "my arrival was announced" but can also be construed as "my existence was predicted". So most can be used with arrival but none strongly imply arrival if the announced event is unspecified.
It's a little informal, but you can "verbify" the (normally, exclamatory) usage...
cooee - used to attract attention, especially at a distance. (oxforddictionaries.com)
...as in many of the written instances of things like...
As he approached, he cooeed loudly, but there was no response.
Apart from that, I do not believe there's a single-word (or simple "compound verb" based on self- prefix or reflexive oneself) English verb with the specific meaning draw attention to oneself, announce one's presence. But I'd be happy to be proved wrong!