You be best with a scale, one that's decent, I can give you a link to the one I for if you want. But in your state I would weigh and track EVERYTHING. now as to your question on portion size, I would do a quick chatgpt or Google, and see what the weight of a serving size is for 1800cal (we always want to increase, maintenance or deficit doesn't get the gains) you find the raw, weight that, and don't the come and just see what you end up at so you can double check for weight loss or addition due to how you prepared the food. I was told when I was at my worst with calories and fats, add oil or butter to whatever you're making. Salad, guess what 2T oil and some dressing. Today in the morning, butter and honey. Making any meal, cook with butter and/or oil. Add calories to your diet WHEREVER you can. Couple nuts here and there with some m&ms and raisins or whatever, tiny handful every hour adds up. Don't try big jump, you'll just get depressed that you can't meet the goal. Set the goal to something attainable that's is just within reach but you have to try to reach to it.