Processed and packaged foods...
...They are so convenient, but they usually add a ton of salt for preservative and flavor enhansement reasons. The very best way to reduce sodium consumption is to reduce the about of processed (including fast) food you consume.
It is easiest done slowly. Pick something that you can fairly easily prepare yourself rather than buying in a can like chili or spagetti sauce (although be careful with canned tomatoes - go for the low sodium versions). You can also try to use the "5 ingredient" rule. If a package of something supposedly edible contains more that 5 ingredients, put it back.
And finally just simplify your diet. Grilled chicken, fish, or red meat, a side salad or steamed veggie, and maybe a serving of rice or polenta. Not much sodium (although red meat does contain some) and totally delish!