What’s the best way to up my protein intake?

I've started using a calorie tracker app to motivate myself to gain weight. Since starting I noticed a ton of things I can improve on, but the biggest is my protein intake. I currently have myself set at 50% carbs, 30% fat, and 20% protein. I've been continuously short in reaching my protein goals and could use some advice. I also have a lactose intolerance which does affect what I eat.

Any advice is welcome! Thank you!