Before I used to talk to some friends who are struggling to make salat regularly, or struggling to practice the deen in general, etc, in a way of "why you have to pray 5x a day and what are the consequences of missing salat, how it's bad to do X or not do X because of X ayat or X hadith, etc". Going on jamaat made me realize the importance of the very basic, of having firm yaqeen & and faith in "La iLLaha iLLAllah, Muhammadur Rasulullah".
Now, first of all, I don't talk, because I know I am not qualified to speak to anyone about the deen, when I need so much help myself. So I try to keep my mouth shut to the best of my ability and speak minimally, even if I am in a situation where I just want to go off (such as TV being watched, music being played, or plans being made to break other commandments of Allah). However, if Allah :taala: chooses to give me an opportunity to talk to a brother about the deen, I do it more from the perspective of "forget about why this guy is so persistent on making his salat on time or why he keeps a beard or why he wears his pants above his ankles, why he does X or why he does not do X, etc, rather let's work on our yaqeen and figure out how we can understand and have firm yaqeen in "La iLLaha iLLAllah, Muhammadur Rasullah", and Insha'Allah everything else will follow.
I also use the analogy (did not invent it) that how they follow their bosses orders 100% at work because they know if they don't follow their bosses rules and orders at work, they have a serious risk of getting in trouble and even getting fired. They follow these orders because they have firm yaqeen that their boss is there, is watching them, and that he will hold them accountable for their actions at work. Allah is our only true "boss" but we don't follow His orders because we don't have firm yaqeen & faith that we will 'get in trouble' or 'get fired (rather get thrown into the fire, Astaghfirullah) if we don't follow His rules and orders... so we go breaking them left and right.
If we had yaqeen in Allah's existence, His authority over us, and His words, as much we have yaqeen in our employer's existence, their authority over us, and their rules & words, then surely we would keep a full beard even if we thought it was impractical (Astaghfirullah), we would wear hijab in all situations where hijab is required and not selectively, we would wear our pants above our ankles even if we thought it looks "weird" in public, we would stop listening to music no matter how much we "enjoy" it, we would stop watching movies, and all in all we would stop trying to make "loopholes" in Allah's deen just to accomodate our desires.
This has seemed to help in some situations. If the conversation seems to take a turn towards something specific, such as "yeah I understand belief in the kalima but why X or why not X, etc", I always try to steer it back to having firm yaqeen in "La iLLaha iLLAllah, Muhhamdur Rasulullah", and I always keep saying that stop worrying about other, "advanced" things, just worry about this one thing and Insha'Allah improvements will happen from there. Only Allah can give hidayat and only He knows best.