How do I keep my darts out of the 5s?

Practice. Practice. Practice 

I move my back foot to the opposite side just a bit.  Changes your angle of approach to the board.   Works for me a lot of the time.  

@deforss Thank you. I will try

Hello, there are certainly many aspects to the technical issues of the litter. My tip is a mental one. In my experience, the more you concentrate on avoiding it, the more often you hit the 5 and the 1.
To "reprogram" my brain in this regard, I came up with this training game: It's called "26". The aim of the game is to achieve a total of 26 points. S20 and D20 each count one point, T20 three points. If you hit the 5 or 1 segment, you don't get any points, but you can't bust either. On all other fields and outside the scoring area, the number of points scored is reset to zero. The interesting thing is that 5 and 1 are no longer something to be ashamed of, but something good compared to 12 or 18 (because you bust there). In this way, one's composure grows when throwing at 20.

Have someone watch your elbow. I would suggest it's moving around. I may be wrong. If you are grouping them in the 5 tho, that is where you are throwing them

If you stand straight-on to the board (toe pointed), then try opening your stance so that your plant foot is opened at a 5 or 10 degree angle towards the 1, rather than perpendicular to the throw line.

Best thing to do is to take some video of your throw to analyze if the cause is alignment or elbow/shoulder movement changing your line of throw. Try to compare a good throw where you hit a 20/60 against a throw where you hit the 5 removed link