Aside from the aforementioned "tossing canon out the window", there are several tricks to keep your campaign within canon, but not interacting with canon. I find myself utilizing this when I put together a new Star Wars game.
Location, Location, Location
One of the first questions I ask myself when creating a new game; when does the story take place? Star Wars has a rich history, even if most of it now falls into the category of "Legends", and is no longer established canon. You've got the Old Republic era, thousands of years before the movies. You could even go farther back than that to the formation of the Republic and the fall of the Infinite Empire, and give the game a real "space fantasy" feel. You could play in the Fall of the Republic/Clone Wars era, or the Dark Times. The product line from Fantasy Flight Games is currently written from the standpoint of the Rebellion Era, and much of the media since Disney took over Lucasfilm has been focused on a return to that time. There's the New Republic era, both in the books from the last 25 years and the newer version that Episodes 7-9 will show us. The Yuuzhan Vong war, the Legacy Era, even farther beyond you could make up your own future where your PCs are Skywalkers, Solos, Antilles(es?), Calrissians, and a host of other famous family members.
So "which era to run" is my first question. Once I have that, the next location to decide is where in the galaxy is the game focused? Some campaigns I've run had no specific central location in the galaxy, they just sort of happened wherever the PCs wanted (or needed) to go. This felt rather epic, as the story swept across the galaxy to a score of worlds the the PCs would likely never come back to. However, the games where I had the most fun were ones that had a central location; a place for the PCs to get familiar with, get to know the people and unique places within, and gave them a sense of "coming home" every few sessions.
I sort of equate it to the difference between shows like Star Trek (Original series or Next Generation) and Battlestar Galactica versus ones like Deep Space Nine and Babylon 5; with one the new location is the exciting discovery or unknown threat, while with the other there's a general desire to protect your home from threats that come to it, or dwell within it. This is a generalization and simplification to be sure, but I hope you get my meaning.
The Right Amount of Seasoning
A sad consequence of growing old was the dawning realization that I can't game like I did in college; not if I want to maintain a healthy social balance among my family and friends. No more weekly games for me, the games typically need to be spread out to months between sessions. This can make sweeping epics very hard to maintain, as I was reminded of with my last campaign "Another Longshot". I have to factor this in to the type of story I want to create with my players; more of a series of connected adventures that could stand alone rather than a sweeping epic that takes years to complete.
The more I write these days, the more it feels like I'm planning on "seasons" for my game rather than sessions. It's like the Rebels cartoon or any of the DC's "Arrowverse" shows on the CW; each episode (or 2-episode arc) deals with a stand alone story. Within that story are plot threads that weave into a larger storyline that will culminate at the end of the season. This give me more of an opportunity to write sessions based on the player's backgrounds, motivations, and complications while still building towards a season finale that ties it all together.
So what happens when you have a desire to run a game in an era that's seemingly been written a thousand times over? I had this mentality for a good fifteen years that I was done with the Rebellion Era; that every story that could have been told within that time frame had been told. I was distracted by the stories being written after the destruction of the Second Death Star, or by those leading up to and including the Clone Wars. But what appealed to me about those eras were that there was seemingly more open canvas in which I could paint my own picture about Star Wars. An uncharted section of space where I determine what happens there in. What I was reminded of recently was that the galaxy is a really, really, really big place. There's plenty of space within the galaxy for me to create a vast and robust story and never have it cross paths with anything already established if I don't want it to.
One of the best resources I've found is the interactive Star Wars Galaxy Map website. It lists out the location of every known sector, planet, and trade route in the Star Wars galaxy. It even links them all to Wookieepedia, so you can look up important details about the planet, sector, or trade route. Taking some time, it's rather easy to find a sector or two that are practically empty; devoid of any meaningful established canon or even "Legendary canon".
Practice Makes Perfect
Utilizing the points I've made thus far, let's look at a potential new campaign. With my rediscovered enjoyment of the Galactic Civil War, I elect to place the campaign in the Rebellion Era. Specifically, I'm really enjoying the years leading up to A New Hope, as seen in the Rebels cartoon and Rogue One. I want to tell a story about a rebellion forming within a specific sector, one that will become a part of the greater Rebellion as a whole, but still focuses on the politics and dynamics within a specific region of space.
Looking at the Galaxy Map, there appears to be a nice and mostly vacant sector in the southern side of the galaxy; the Tantra Sector. According to Wookieepedia, there really hasn't been much established there, especially within the new canon. There have been only the barest mention of anything about the sector in Legends canon, even though the sector lies between two of the major galactic trade routes. I can see the sector being heavily colonized within easy reach of those trade routes, with most of the interior of the sector barely touched (or even explored). Entire planets of beings could lie in that region and have yet to be discovered, or lost colonies could have thrived there waiting to be brought back into galactic society.
This region of space, and the era it's in, gives me a huge amount of real estate to create planets, organizations, and plot points for. I can lay out details for the Imperial's control of this sector, outlining the military strength of the Sector Fleet and the general personality and machinations of the Moff in charge of the sector. I can create several worlds to fill specific roles within the sector; population centers, manufacturing locations, agro-worlds, shadowports where criminals thrive, and lost colonies that simply want to be left alone. Pirates who threaten the spacelanes and bounty hunters who hunt them down for sport and profit. Lost temples or starships that hold secrets of the Force...
And of course, dissidents who balk and refuse to submit to the will of the Empire and who have chosen to be rebels.
This could be a fun place to play, a corner of the sandbox that I can build what I want and how I want it. It can be a familiar place for the players to have meaningful effect on, yet close enough to the "galactic highways" that an adventure could take them across the galaxy if need be.
Where you place your story is almost as important as what your story is. A good location can make a good game great, a sweeping plot-line epic. It provides players with a sense of familiarity, and can be something to motivate your players to action when you threaten "their home". Be sure to give a lot of thought to how much freedom and space your location provides, and enjoy the time you spend coloring within those lines.