Anytime! here's my recommendation:
1. Read about all sorts of business ventures and biographies you can find. (How did google start? Netflix? Who's warren buffet? etc)
2. Read about the structure of a business plan and the pitch deck. It doesn't require a genius. You should know how to construct some graphs and analyses. Yet what you really should do is to think on behalf of the client and use your knowledge of step 1.
3. Check out as many business plans and decks as you could find.
4. You'll need a designer. Initially, you can buy a Powerpoint template or download one, but later on, specify part of your budget for a designer you'll be dealing with. (You'll also need a financial expert unless you want to do the financials -- You'll have to do some research on how the numbers work, a little bit of accounting self-study.)
5. Research the biggest VCs and Accelerators in the world, you need to know them. See what they're recommending. They recommend pitch deck and business plan structures, follow them.
That's good enough. Build a portfolio, for fun create a deck or two about companies you wanted to build to put as a portfolio if you wish.
Again, I can't stress on step 1.
Read, Research, and time. That's all you need.
Best of luck,