How can we be filled with the Spirit today?
Thank you for your question.
To know what 'full of the Spirit' means we have to look at what the Bible says about those that were filled with it.
Deuteronomy 34:9 And Joshua the son of Nun was full of the spirit of wisdom; for Moses had laid his hands upon him: and the children of Israel hearkened unto him, and did as the LORD commanded Moses.
Exodus 31:2 See, I have called by name Bezaleel the son of Uri, the son of Hur, of the tribe of Judah:
3 And I have filled him with the spirit of God, in wisdom, and in understanding, and in knowledge, and in all manner of workmanship,
2Ki 2:9 And it came to pass, when they were gone over, that Elijah said unto Elisha, Ask what I shall do for thee, before I be taken away from thee. And Elisha said, I pray thee, let a double portion of thy spirit be upon me.
15 And when the sons of the prophets which were to view at Jericho saw him, they said, The spirit of Elijah doth rest on Elisha. And they came to meet him, and bowed themselves to the ground before him.
Isaiah 11:2 And the spirit of the LORD shall rest upon him, the spirit of wisdom and understanding, the spirit of counsel and might, the spirit of knowledge and of the fear of the LORD;
John 3:34 For he whom God hath sent speaketh the words of God: for God giveth not the Spirit by measure unto him.
Eph 5:18 And be not drunk with wine, wherein is excess; but be filled with the Spirit;
19 Speaking to yourselves in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord;
20 Giving thanks always for all things unto God and the Father in the name of our Lord Jesus Christ;
Luke 1:41 And it came to pass, that, when Elisabeth heard the salutation of Mary, the babe leaped in her womb; and Elisabeth was filled with the Holy Spirit:
42 And she spake out with a loud voice, and said, Blessed art thou among women, and blessed is the fruit of thy womb.
Luke 1:67 And his father Zacharias was filled with the Holy Spirit, and prophesied, saying,
68 Blessed be the Lord God of Israel; for he hath visited and redeemed his people,
69 And hath raised up an horn of salvation for us in the house of his servant David;
70 As he spake by the mouth of his holy prophets, which have been since the world began:
71 That we should be saved from our enemies, and from the hand of all that hate us;
72 To perform the mercy promised to our fathers, and to remember his holy covenant;
73 The oath which he sware to our father Abraham,
Acts 2:4 And they were all filled with the Holy Spirit, and began to speak with other tongues, as the Spirit gave them utterance.
5 And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven.
6 Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language.
7 And they were all amazed and marvelled, saying one to another, Behold, are not all these which speak Galilaeans?
8 And how hear we every man in our own tongue, wherein we were born?
11...we do hear them speak in our tongues the wonderful works of God.
Acts 4:8 Then Peter, filled with the Holy Spirit, said unto them, Ye rulers of the people, and elders of Israel,
9 If we this day be examined of the good deed done to the impotent man, by what means he is made whole;
10 Be it known unto you all, and to all the people of Israel, that by the name of Jesus Christ of Nazareth, whom ye crucified, whom God raised from the dead, even by him doth this man stand here before you whole.
Acts 6:3 Wherefore, brethren, look ye out among you seven men of honest report, full of the Holy Spirit and wisdom, whom we may appoint over this business.
5 And the saying pleased the whole multitude: and they chose Stephen, a man full of faith and of the Holy Spirit, and Philip, and Prochorus, and Nicanor, and Timon, and Parmenas, and Nicolas a proselyte of Antioch:
Acts 7:55 But he, being full of the Holy Spirit, looked up stedfastly into heaven, and saw the glory of God, and Jesus standing on the right hand of God,
Acts 9:17 And Ananias went his way, and entered into the house; and putting his hands on him said, Brother Saul, the Lord, even Jesus, that appeared unto thee in the way as thou camest, hath sent me, that thou mightest receive thy sight, and be filled with the Holy Spirit.
From this small selection we see that being ‘full of the spirit’ is manifested in different ways in different persons.
This is explained by Paul as follows:
NIV 1Corinthians 12:1 Now about spiritual gifts, brothers, I do not want you to be ignorant.
2 You know that when you were pagans, somehow or other you were influenced and led astray to mute idols.
3 Therefore I tell you that no-one who is speaking by the Spirit of God says, "Jesus be cursed," and no-one can say, "Jesus is Lord," except by the Holy Spirit.
4 There are different kinds of gifts, but the same Spirit.
5 There are different kinds of service, but the same Lord.
6 There are different kinds of working, but the same God works all of them in all men.
7 Now to each one the manifestation of the Spirit is given for the common good.
8 To one there is given through the Spirit the message of wisdom, to another the message of knowledge by means of the same Spirit,
9 to another faith by the same Spirit, to another gifts of healing by that one Spirit,
10 to another miraculous powers, to another prophecy, to another distinguishing between spirits, to another speaking in different kinds of tongues, and to still another the interpretation of tongues.
11 All these are the work of one and the same Spirit, and he gives them to each one, just as he determines.
28 And in the church God has appointed first of all apostles, second prophets, third teachers, then workers of miracles, also those having gifts of healing, those able to help others, those with gifts of administration, and those speaking in different kinds of tongues.
29 Are all apostles? Are all prophets? Are all teachers? Do all work miracles?
30 Do all have gifts of healing? Do all speak in tongues? Do all interpret?
31 But eagerly desire the greater gifts. And now I will show you the most excellent way.
Can I suggest that you read this:
If you then have further questions please ask.
I hope this helps