I visited Torres del Paine national park's visitor center in Chile a while ago, though I didn't do the hike to see the actual Torres del Paine because I overslept and it was already too late in the afternoon by the time I gained the energy. I underestimated how easy it would be to hike. I didn't even know that I had to do my hike during the morning to avoid thunderstorms at high elevation.

I want to do some hiking in my area (Denver) so that doesn't happen again. I doubt there's as strict a time limit unless I'm in Rocky Mountain National Park or doing a trail at a high elevation, but I'm still very much a noob. What do I need to bring (besides water)? How do I train myself to take on harder hikes? What times are best to hike? How do I search for trails?

I eventually want to be able to do a multi-day hike/backpacking (e.g. that one super long hike to Macchu Picchu), though I want to start simple for now.