By asking for it
(Luke 11:13 NIV) If you then, though you are evil, know how to give good gifts to your children, how much more will your Father in heaven give the Holy Spirit to those who ask him!”
Non-Charismatics response
The disciples were now not to receive the Holy Spirit in answer to their own petition, but in answer to Christ’s petition. Hence today the Holy Spirit is given to all who believe, because of Christ’s prayer, without the individual asking for it.
At the end of Christ’s earthly ministry, he said: “I will pray the Father, and he shall give you another Comforter, that he may abide with you forever”. (John 14:16).
Charismatics response
Luke 11:13 is not talking about Christ’s prayer for the Holy Spirit. It is talking in the plural about God’s children asking for the Holy Spirit from the heavenly Father.
Laying of hands
Joshua is qualified for leadership by the Spirit (Num_27:18). In this and in Deu_34:9, Joshua is represented as possessing the Spirit through the laying on of the hands of Moses. This is an interesting Old Testament parallel to the bestowment of the Spirit by laying on of hands in the New Testament (Act_8:17; Act_19:6).
However, it is not always the case that the outpouring of the Spirit needs to accompany the laying of hands. Note the instance of Cornelius.
(Acts 10:44-46 NIV) While Peter was still speaking these words, the Holy Spirit came on all who heard the message. {45} The circumcised believers who had come with Peter were astonished that the gift of the Holy Spirit had been poured out even on the Gentiles. {46} For they heard them speaking in tongues and praising God.
While Peter was speaking, not when he was laying hands on them, the believers received the Holy Spirit.