Most people have a financial adviser, but for the industrious I recommend:
http://jlcollinsnh.com/stock-series/
And for the lazy, this is a good resource: https://www.bogleheads.org/wiki/Lazy_portfolios
And for the lazy, this is a good resource: https://www.bogleheads.org/wiki/Lazy_portfolios
*(Actually, looks like it depends on your source: 48%[1] or 52%[2], so let's say "about half of people")
1: http://money.cnn.com/2015/04/10/investing/investing-52-perce...
2: http://www.gallup.com/poll/190883/half-americans-own-stocks-...