The Holy Spirit is the Spirit of the church. By this I don't mean to suggest that God's SPirit cannot exist outside of nor act outside of Christian churches. What I do mean is that the Holt Spirit is constitutive of the church. Pentecost was the fulfilment of the prophetic expectation of the eschatological age (Joel 2.28-30 cf. Acts 2.1f). Furthermore, the Spirit is given to all peoples (Acts 8.14-17, 10.44, cf. Mt 28.18-20) without distinction. I believe Christianity to be genuinely inclusive in the sense that anyone may believe and belong (although there is a price to be paid - to belong, one must swear and exhibit proper alliegence to Christ).
Baptism brings us into the work begun at Pentecost, into one body (1 Cor 12.12-13). This is the pneumatologically constituted body wherever it meets. Every believer has been baptised by the Spirit (1 Cor 12.3). There is a wonderful sense of egalitarianism in this sort of Pneumatological spirituality (if that isn't tautological). Christians who inwardly divide do so against the warp and woof of the nature of the church.
The practice of the Christian life is other focussed. The Spirit is power to witness to Christ to others (Acts 1.8; Jn 15.26, 16.8-11). The Spirit’s gifts are dispensed by him (1 Cor 12.11) for service in the church (Rm 12.6-8).
There is no room for ego (Rm 12.3), self-depreciation (1 Cor 12.13-20) or independence (v21-26). Each individual is important (v27). The uniqueness of Pentecost and baptism in the Spirit identifiable with (often unconscious Jn 3.8) regeneration implies there is no second class Christian. Being filled is an ongoing command to the whole church (Eph 5.18-21), accessible to all Christians (Jn 7.37-9).
I am in limited agreement with Millard Erickson in his suggestion in Christian Theology that one can and should pray to the Holy Spirit. Baptism (Mt 28.19) and Paul’s benediction (2 Cor 13.13) involves prayer to the Spirit. However, there does not appear to be prayers directed to the Spirit alone in the New Testament. The Spirit intercedes for us in prayer (Rm 8.26-27), teaches us (Jn 14.28) and convicts us (16.8-11). As God, he is worthy of worship, but with regards to prayer, he is self-effacing.
Just a few thoughts.