Looking for weight gain tips (tired of hearing "just eat more")!

I don’t weigh myself often but I’m guessing I’m currently about 108 lbs. I am 5’5”. So, very slim. And I have always been this way – all through high school I was made fun of for being “bulimic” – which I most certainly am NOT. I was a sickly child and have never had much of an appetite, but I do eat. I am sick of people telling me to just eat more… because I never gain a pound! Obviously I realize that I need to increase my calorie intake if I want to gain… but are there any other things I can do? I don’t want to look “sick” on my wedding day!