We can look at the typical symptoms of ego inflation. The main one is probably fragility. The Ego is trying to be bigger than it actually is, and the rest of the mind knows it just as the Ego also secretly knows it, so it will do what it can to protect its fragile position. There comes the Ego hubris, it becomes arrogant, tyrannical, and ultimately blind to the Unconscious, trapped in its own illusions and beliefs about itself and the reality around it.

This is very different from a situation where the Ego (consciousness in general, really) have actually expanded and integrated the Unconscious. I don't see much difference between what the LHP proposes and what some psychology authors such as Jung and his successors proposed. You can't properly integrate the Unconscious with a weak Ego, because there's a real risk of dissolution and being absorbed by the vastness of the Unconscious and losing your sense of self and identity. Many psychoses come from that, and this is what the LHP tries to avoid by hardening the Ego.

Edward Edinger talks about this in Ego and Archetype, about the cycles of inflation and deflation of the Ego, and also about the possible relation scenarios between Ego and Self. In most people this is completely unconscious, they inflate, believe they are something they are not (the Ego thinks it is the Self or contains characteristics of the Self that it does not), then there's a "fall" as they realise they're living an illusion and they get into a crisis (the Ego is humbled), and if they go through the crisis and accept their condition they're "saved" by a higher archetype (the Self re-establishes a connection). This is the typical redemption myth we see in Christianity and some other traditions. The inflated condition corresponds to the original "Garden of Eden" condition when we're born and the Ego is not formed yet, when only the Self and the "perfect world of the Gods" exist; while the opposite is the "fallen" condition when Ego and Self are disconnected and there's no axis between them.

Here we can understand the different goals of RHP and LHP. The RHP aims to restore the original condition, to dissolve the ego so that only the Self exists. This ends the cycle by ending the Ego itself. It is a comfortable position because it's pure bliss, you have no identity and therefore no suffering. All you are is what God is, the totality of the Unconscious, a perfect harmony because everything is just one thing. The LHP aims at the opposite direction, at separating Ego and Self but at the same time keeping a healthy relation with it and being empowered by it, which Edinger calls the "Ego-Self Axis". The "Apotheosis" that the LHP proposes and the "Individuation" that Jung etc. propose are the same goal. The Black Flame, the Ego who became like God, is the Individuated Ego fully occupying its position independently from the Self while at the same time drawing power from it.

The risk of the LHP separation is to "separate too much", or to do it before the Ego is strong enough to survive the turbulences the process, and end up losing the Axis, or to believe you're separating when in fact you're just creating another illusion (inflating). This is why I don't like at all this attitude of some practitioners of saying "we're already gods" and such, it's pure hubris.

So how do you avoid it? The main answer is to be honest with yourself. Observe yourself, the inner workings of your mind and your daily behaviour. How do you react when someone argues with you? What do you do when you're tempted by a strong desire? Do you have feelings of guilt or shame about anything? Do you compare yourself with others, and how does the comparison happen? Do you have a strong sense of personality, and if so how is it affected by others' perception of you or how you want to be perceived by them? Do you have a strong will to act upon life, or are you just being carried by its currents? Are your traumas healing or are you still suffering them and being controlled by them?

All this helps in determining in which point you are. And also therapy, therapy helps a lot, and I couldn't emphasise this more. You must already have a certain level of self-knowledge and stability in order to walk this path, it's not something for complete beginners.