By the look of it is a common phrase used to express an observation or assumption based on the appearance of something or someone. If you want to sound more varied in your language, here are some synonyms you can use instead: based on appearance, apparently, evidently, it seems, judging from, it appears, it seems like, looking at it, observation suggests, from what I can see, from what I gather, seemingly, to all appearances, to judge by, to the naked eye. By using these synonyms, you can add variety to your sentences and express your meaning more accurately.