The adjective advantageous is useful for talking about things that are beneficial, or helpful, like when you find an advantageous spot to hang your yard sale sign — a spot where all the passing cars can see it.
Anything that creates an advantage is advantageous. You could describe your decision to throw a huge party as advantageous for your social life, or the cooking class you took as advantageous to the success of your catering business. If it helps you get what you want, or is generally useful, it's advantageous. The root is the Old French word avantage, which means "advantage, profit, or superiority." Anything that assists in your pursuit of these things is advantageous to you.
adj giving an advantage
promoting or enhancing well-being
involving advantage or good
serving to promote your interest
suitable or at a time that is suitable or advantageous especially for a particular purpose
yielding material gain or profit