Here are placements so far going just off what we have in the movies.
Iron Man
The Incredible Hulk - unknown, but definitely before Iron Man 2
Iron Man 2 - 6 months after Iron Man
Thor - A few days after Iron Man 2
The Avengers - Anywhere from a few months after Iron Man 2 and Thor to a year and a half. As explained earlier, Fury's "last year" comment could be as little as a few months if The Avengers happens in spring and Thor happened in fall.
Civil War - a "few years" after The Winter Soldier, at least "2 years" (both quotes according to Falcon.) "Four years" after the collapse of SHIELD (TWS) according to General Ross. "Eight years" after Iron Man according to Vision.
Homecoming - two months after Civil War and eight years after The Avengers according to words on screen. Eight year figure is reinforced by Vulture's dialogue. Between Vision's dialogue in CW and the events in Homecoming, we know that Iron Man and The Avengers are separated by a year and a half at most.
Iron Man 3 anchors Avengers to 2012 while Homecoming anchors it to 2010. They are, however, factually incompatible. Many are viewing this as a mistake, but it's clear to me that this is a retcon. When their latest efforts like CW and Homecoming are in agreement, that indicates that forethought and planning was put into this change by the studio. The result will be that Homecoming 2 will come out the same year it takes place in-universe (2019.)