New here (need style advice)

[StyleElyts]

Hey everybody, I found this forum and it looks good here. I hope to gain some knowledge from this website.
There are few style issues I currently cant figure out, so if you would be able to give me some advice, it would be really awesome.
Here are my questions:

1.What clothes go with ankle sneakers? I would like to buy a pair of ankle sneakers but I dont know what clothes to wear with them? I usually wear denim pants and a lot of flannel shirts and since its winter now and I wear leather boots, its goes well together. But when it gets more warm and I will have to wear sneakers, what top(torso) clothes should I wear? What goes best with those ankle sneakers?

2.Also Im thinking about buying leather shoes. But Id like something more casual. Id like something that wouldnt make my feet suffer in warmer days. But I dont want moccasins. Do you have any suggestions?...

3. ...Id like to buy those leather shoes because I think those are type of shoes which would fit perfectly to some of my button up shirts and dresshirts. Id like to wear those shirts and dress shirts with some denim jeans probably. Do you have any suggestions for other appropriate type of pants to wear with those shirts? Or are jeans ok? I thought maybe some darker/black jeans or white jeans..or completely different material? What do you think? And should it be slimfit or what type?

4. What footwear goes the best with flannel shirts except leather boots? Something for warmer days. Im not a hipster though, I have more of a country style but I cant figure out what footwear to wear during spring/summer.

5. Last question: When to wear shirts untucked and when tucked in? I have thick warm flannel shirts, also flannel shirts which are very thin and light. I also have other shirts which are little bit more elegant (those which I thought buying leather shoes for). I really have no clue when to tuck it in? is it only up to me? Or is it, when the shirt is too long on my torso? And can every shirt be tucked in no matter how thcik it is?
Also what shoes to wear when its tucked in? Because in my opinion, sneakers would be inappropriate. What do you think?

Thank you.