All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Indeed, you did well by restricting yourself to drawing flowers, trees and the like and by avoiding drawing the pictures of animate beings. We ask Allaah to provide you with the Halaal means of livelihood.
A Muslim is not permitted to take part in any forbidden or innovated acts whether his participation is by his physical presence, by drawing signs, making signboards, writing phrases of congratulation or invitation to such celebrations; the rule is the same. All this is forbidden.
Those gifts, which are sold throughout the year and are not restricted to the mentioned occasions, are permissible. One may make them and sell them even if some people may use them in forbidden occasions.
As for making signs of shops or advertising them, then this depends on the nature of the shop.
A. If the commercial sectors are known for their forbidden activities such as a dance hall, cinema house, casinos, night clubs, usury taking banks etc., then making any kind of advertisement for such sectors is forbidden whether it is a signboard, a slogan, or the like.
B. If a restaurant is known for serving pork only or alcohol only then providing any service for such restaurant is forbidden.
C. If a restaurant serves Halaal and Haraam, both kinds of foods, drinks, etc., this is a doubtful matter, and thus it is safer to avoid dealing with it.
D. If a shop or a, restaurant, is known not to provide Haraam things or its state is not known, then making signs for it or advertising it is permissible.
Allaah Knows best.