Make a list of all the things that first attracted you to him or her ,not so much the physical attributes but things like ...I liked the way you complimented me on my hair or when you ask me if theres anything I need , or helping me out without me having to hint or right ask you to give a hand.
An unexpected phone call or love note. Serving him dinner in fishnets and a frilly apron. Learn a few basics about his favourite sport or hobby ,so you can genuinely take an interest. It will be the gesture that means the most.
Use kind words, show interest, smile and encourage as often as you can. Surprise him or her ,ask them out for dinner or breakfast in bed. Take an evening stroll and present them with a small personal gift ,doesnt need to be expensive , the surprise itself is the key. Shows you were thinking of them.