Actions taken to transfer merit What do you have to do in order to transfer merit. Do you just do something wholesome, and wish for someone else to receive the karmic result? Etc…?
From the book What Buddhists Believe by Venerable K. Sri Dhammananda Maha Thera:

Buddhism also teaches that the acquired merit can be transferred to others' it can be shared vicariously with others. In other words, the merit is 'reversible' and so can be shared with other persons. The persons who receive the merit can be either living or departed ones.
The method for transferring merits is quite simple. First some good deeds are performed. The doer of the good deeds has merely to wish that the merit he has gained accrues to someone in particular, or to 'all beings'. This wish can be purely mental or it can accompanied by an expression of words.
This wish could be made with the beneficiary being aware of it. When the beneficiary is aware of the act or wish, then a mutual 'rejoicing in' merit takes place. Here the beneficiary becomes a participant of the original deed by associating himself with the deed done. If the beneficiary identifies himself with both the deed and the doer, he can sometimes acquire even greater merit than the original doer, either because his elation is greater or because his appreciation of the value of the deed is based on his understanding of Dhamma and, hence, more meritorious, Buddhist texts contain several stories of such instances.
The 'joy of transference of merits' can also take place with or without the knowledge of the doer of the meritorious act. All that is necessary is for the beneficiary to feel gladness in his heart when he becomes aware of the good deed. If he wishes, he can express his joy by saying 'sadhu' which means 'well done'. What he is doing is creating a kind of mental or verbal applause. In order to share the good deed done by another, what is important is that there must be actual approval of the deed and joy arising in the beneficiary's heart.

I encourage you to read the whole page devoted to this (linked above). There is a lot of interesting supplemental information including the reasons for transferring merit to the deceased and the right and wrong way to go about doing this.
The Author refers to the Tirokudda Kanda sutta which you may find interesting.