Well, most of my sources are gonna be in spanish because that's sort of the best way to go about this, but of course going straight to the source with things like the "Cartas de Relaciones" from Cortez or the "Relación de los primeros descubrimientos de Francisco Pizarro y Diego de Almagro". And that's just mentioning the big names of famous conquistadores, I'm reading Cabeza de Vaca's log currently, actually. In particular I recommend finding material related to Gonzalo Jimenes de Quesada as he was known as an intellectual and writer.

I've read "Proceso historico al conquistador" is a really good source to understand the mentality of the conquistador.

And well... it'll really differ a lot. As in, as it shouldn't be much of a surprise, conditions were very different all across the Americas, so what you had to see in Aztlan was very different from the Inca lands from what'd you see in the Mapuche frontier.

Some broad generalizations can be made of course, conquistadores were first and foremost entrepreneurs, they had the means to carry on an expedition and more often than not had to report back to the crown, so keeping a log of events is relevant. They had, of course, military experience already from being fresh off the Reconquista and had a surprisingly good capacity to adapt swiftly to the local cuisine and whatever food they could scrounge up in their exploratory path. Hunger, fear and sickness was of course common amongst the conquistadores.

The bands were relatively small and of course relied a lot on indigenous help to keep going, given the extremely hostile and unknown circumstances they found themselves in.

It's difficult to say much more than these broad generalizations given such a wide area you're searching, sure they all came from Spain (well, almost) but the conditions they met within the different parts of the Americas are so drastically differnt I can't quite pin down what you're looking for exactly.