Simmer uncovered to evaporate excess liquid
Cook longer over low to medium heat
Add tomato paste
Stir in a cornstarch slurry
Mix in a flour slurry
Add a small amount of mashed potatoes
Blend in cooked vegetables
Stir in breadcrumbs
Add grated cheese
Use a roux
Puree part of the sauce
Reduce added water or broth next time
Drain excess liquid from tomatoes before cooking
Add a small amount of arrowroot slurry
Stir in instant potato flakes