I would say: read a lot :). There are quite a few accessible books (I mean: books you will actually read ;) ) that have some valuable information.
I would say: start for instance with 'the little book of common sense investing'.
You'll find other 'little books' interesting too... Easy reads, easy starting points...

What do you see as 'long term'? Months? Years? Decades?
Have a look at the long term evolution of the stock market.. Long term probably means 'decades' before you can say 'the stock market always goes up'.

Have a look at systematic investing: frequently invest an amount of money. Whether stocks go up or down, keep on investing that... Sounds easy but sentiment makes it harder than you would think.

Be very careful with stock ( or crypto) picking.
No one here can guarantee a certain stock or crypto coin will be a good investment in the long term.
We all assume that blockchain / crypto currencies are here to stay. Though no one can tell which crypto currencies will still be here in ten years...