Instagram and other photo filter software are great. But, aging your photos manually can create a more organic feel. Start with your base photo. Crop as needed.
Increase exposure moderately. Reduce contrast by roughly 10-20% (depending on your software). This will assist in simulating the fade aged printed photographs posses.
Reduce saturation by roughly 10-20%. Increase brightness by the same percentages. Early vintage films weren't as accurate at reproducing color as today's digital cameras.
Increase color temperature generously. Reduce contrast yet again by 10-20%. Vintage films tend to have a warmer temperature palette. Early automatic cameras don't reproduce contrast well.
Increase "noise" or "grain" (depending on software) considerably. This reproduces lens artifacts and errors in developing.
Finally, add a shadow or vignette to darken the edges of the image. Again, this will reproduce the poor lens quality of early automatic cameras.
Those are the basics. Now go have fun tweaking these settings and create something incredible without the limitations of filters. Happy Shooting! -nowhere_usa