As with all other writing scenarios, romance writing can also be divided into two sections: inside feelings and outside actions of your character. These two make up most of your scene and it is entirely up to you which one you prefer. Personally, I like to take the former approach and look inside - you see, most people are a hot mess when it comes to love. :) A thousand thoughts race through the mind, each shouting louder than the last as they have a hell of a time trying to choose what to believe in and what to really think. People's state of mind can tell a lot about their personality, and either give them a defining attribute right away or give space to character growth: some might regard the stammering, awkward guy as 'cute' or they could learn and grow into a suave charmer with some experience!
I've also written with people who are big on writing out the character's surroundings and actions, often subjectively. For example, an otherwise completely ordinary café can very well turn into the seventh heaven when 'tinted' with love. This also applies to any other emotion - everything is relative, after all.
Also, the five senses each give a unique perspective on the events playing out, and leveraging them effectively creates, in my opinion, an incredible scene. You can start out with an objective description which twists and turns as new impulses register with your character, or you can focus on something distinct: be it the fragrance of a perfume, the touch of a hand or the pierce of a gaze... Think about it, what is the one aspect of the other that would grab your character's attention immediately?
Of course, moderation is recommended whichever way you take. Writing out feelings, actions and words in great detail can work out well for even the smallest gesture, just make sure not to make it look like your poor character is having an orgasm because the potential loved interest smiled at them.
...unless that is the type of people they are!
