Who should one follow? Who should be our guides for life? It is clear that we alone do not know all of the answers and there is much to learn and gain from the insights of others.
Everything we believe is based on premises that we may or may not be conscious of [usually not]. If one truly, honestly and sincerely believes that אין עוד מלבדו then that will inform and impact all of his beliefs and opinions. If he does not, then that will also impact his opinions.
One could be an observant Jew but still not believe so much in Hashem. Where do you find such people? EVERYWHERE. The person who is suffused with a deep, unremitting belief that Hashem is everything is actually quite rare. Most people have other values that compete with Hashem [such as their קנאה תאוה וכבוד etc. etc.]. The greatest believer in Hashem [possibly] in the previous century was Rav Yechezkel Levenstein. As the Chazon Ish said - Rav Dessler has Hashem in his mind, Rav Elya Lopian in his heart and Rav Chatzkel - in his hand. As real as anything. He would constantly remind his students in Mir and Ponivitch that Hashem exists [!!!]. These are the top Yeshiva boys in the world. Do they need an Aish Discovery seminar? It turns out that ... yes. R' Chatzkel said that he worked for 40 years on his Emunah and if he skips a day he feels it weakening [!!!]. The gold standard in Emunah is R' Chatzkel. Everybody has moments where they just KNOW it is true, but the test is to live like that every second.
So who should one follow? From whom should one seek advice? The more a person believes that Hashem is EVERYTHING and that nothing else matters other than following His will - the more his opinion on any given matter carries weight. The Ramban says that there is a מצות עשה דאורייתא to remember מעמד הר סיני that יהיו עינו ולבנו שם כל הימים - our eyes and hearts should be there all of our days. Everything we see and feel [עינינו ולבנו] should be through the prism of מעמד הר סיני [HaGrama"sh ztz"l]. A person who is living סיני is a good candidate to be a worthy guide.
I am so utterly suspicious of people who are spiritually lax in so many areas [and are almost always addicted in differing degrees to their smartphones] but when it comes to "their thing" [it could be army service for all, or that the army is glatt treif, getting a secular education, or not getting a secular education, making Aliyah (few people are קנאי about not making Aliyah although I have a left wing secular cousin who is קנאי about not entering the "captured territories), loving the Medinah, hating the Medinah etc.] - all of the sudden פנחס בן אלעזר בן אהרן הכהן comes out in full force and קנאות takes the day. Not קנאי about קדושה. Not קנאי about davening with כוונה and preserving קדושת בית כנסת. not קנאי about smiling at every person they meet [הוי מקבל את כל האדם בסבר פנים יפות], not קנאי about being completely honest, not קנאי about ואהבת לרעך כמוך, not קנאי about not spending excessive amounts of money on pampering themselves when other Jews lack the basics. But super קנאי about "their" issue.
Often, young, idealistic people get into arguments with older often cynical people [sometimes their own parents] who try to convince them that while being "religious" is important, one has to live in the "real world". This is just עמלק מדבר מתוך גרונו. We all [teach sifrei chasidus] have a little עמלק in our hearts and sometimes it rears its ugly head.
So let us seek true Tzadikim who are 'דבקים בה and they will be our guiding lights. When other people express opinions - you may be polite [usually - particularly if it is a parent or elder] but know in your mind and heart that their opinions are predicated on the belief that there are other values in life outside of Hashem and His Ratzon and mitzvos.
This doesn't make them bad people. Just not people who deserve to be מורי דרך - guides for becoming the greatest Tzadik you can be.