Easiest way to increase your calories is to favour real whole foods (rather than focus on "nutrition") that come already balanced from nature... chicken with the skin on, full-fat cheese, regular ground beef, cold-water fish, raw nuts, avocados, butter, cream, green leafy vegetables etc...
Ideally use the best sources for real whole food food that you can: farmer's markets for fresh green produce, grass-fed beef etc... avoiding processed and packaged "foods" which tend to come with too many refined/concentrated sugars and starches.
Prepare meals at home more often than not.
As above there is no need to avoid natural fats (even saturated -- which is the way we store fat on our own bodies) but I personally skip the man-made vegetable oils as these tend to be industrially processed and unbalanced with too many omega 6s... these are pro-inflammatory.
I (like every other animal on the planet) do not count calories, nor do I count carbs, fat or protein these days; as I have established through BG testing which foods are best to help me manage my BG levels.
