Several food logging and diet apps will give you the macro and micro nutrient breakdown of your daily intake if you accurately log everything you eat, thanks to an extensive database of food items. For example, if you log "1 medium sized banana" it will tell you how many calories, grams of protein/fat/carbs, fibre, cholesterol, and the spectrum of vitamins and minerals for the banana...along with your % of RDA. Thus you can track your levels of all the essential nutrients to see what your regular eating patterns are like for real nutritional value, how they stack up. I recommend trying this for 3 or 4 days minimum, preferably one week. Do it when you are eating "normally" - not during festive season with dinner parties and cocktail buffets or when you are on vacation in a foreign country eating foods you are not accustomed to.
For my part, I have to work the hardest at getting enough potassium (I aim for 200% RDA of everything, except for vitamins C and K where I'd prefer 400-600%) and vitamin E. The B vitamins are easy to overshoot as is - unfortunately - sodium. I usually get 300% RDA for sodium, but then again my RDA defaults to 1500mg per day and I eat a lot of seafood. I aim for 50g fibre per day and as little sugar as possible. If I consume dried fruit or carrot sticks for a snack that boosts the sugar intake. At least I don't consume processed foods that hide a lot of sugar - for example regular bread, sauces, instant meals and soft drinks.
If you find that your results are not balanced then add or subtract foods which will bring you into better balance. Final option - especially when you are travelling or during party season - is to take a good multivitamin and mineral supplement. I can make some recommendations there if you are curious :-)