The first chord of a progression or cycle will set the tone of the progression and the overall section. Because of this, it is arguably the most important chord of the progression. In order to create an effective progression, you should consider what kind of feeling you are trying to create.

To begin with a sense of:

stability/balance/direction - I chord

openness/exploration/reflection - IV chord

drama/conflict/intensity - V chord

melancholy/gravity/introspection - vi chord

It’s also important to consider how you want each phrase or cycle of the progression to end. The last chord is the second most important chord of your progression. You generally will want to use I, V, IV, or vi to end the phrase, unless you want to create a cyclical pull back to the start of the progression at the end of each phrase.

To end with a sense of:

tension/climax/building - V chord

openness/calm/drifting - IV chord

resolution/finality/stability - I chord

grief/solemnity/introspection - vi chord