You need to show your romantically interested soon. You've went too long without being anything but friends. So ask her to hang out with you and tease her, flirt with her, etc. Find a reason to touch her and let her feel comfortable around you but don't go overboard and shove your tongue down her throat lol...Make sure the day is just fun and you go someplace that you have a lot of things to talk about where you can converse and interact with one another.
This is the best advice I can give you considering it seems as though you've been friendzoned (you said it yourself that she's your best friend) and to get out of the friendzone is near impossible the majority of the time.
In my experience, there are two ways this situation can go. She can either feel the same way about you as you do her and become your girl or she'll give you the "let's just be friends" speech and things will be seem even more awkward between the two of you.
If she feels the same way about you, great; if she rejects you, then move on and pursue other girls.
This is the best advice I can give you considering it seems as though you've been friendzoned (you said it yourself that she's your best friend) and to get out of the friendzone is near impossible the majority of the time.
In my experience, there are two ways this situation can go. She can either feel the same way about you as you do her and become your girl or she'll give you the "let's just be friends" speech and things will be seem even more awkward between the two of you.
If she feels the same way about you, great; if she rejects you, then move on and pursue other girls.