Lets start at the very beginning so, Mulligans.
Sometimes it can be seriously hard to say what hand is good and what isn't. Easy way to look it is that you want few cantrips, then the hand is almost always keep. Few lands, ritual or two and some cantrips is what starting hand usually looks like. You don't want Storm cards in your opener because they are just dead cards and you dig for them anyway while going off. But you can always discard them to Faithless Looting, same with Past in Flames. Pyromancer Ascension is always nice to have but its not worth to mull just for it.
You will learn mulling just by playing the deck, so if you are interested, do that!
After you have found playable hand you just start cashing in your cantrips. If you don't have Pyromancer Ascension in hand don't start with Thought Scour because you don't want to mill your Ascensions.
Usually just slamming Pyromancer Ascension fast as possible is good idea, but sometimes it's worth to cast more cantrips in turn 2 and just drop it on turn 3.
If you have Manamorphose just play it as cantrip if you are searching for Pyromancer Ascension.
Always make sure that if you draw multiple of same card cast only one of them because all the rest makes counters for Pyromancer Ascension. But of course with cantrips you have to just cast them in order to find Pyromancer Ascension at all.
And in scrying, looting or what ever you are doing always prioritize cards that you already have in hand so stacking Pyromancer Ascension gets much easier.
Search for Azcanta
Feels like dead card sometimes so if you already have Ascension and other stuff going try to discard it or scry it away as it doesn't really play any role on storming itself.