Make use of Data Binding

Instead of manipulating the behavior of your control

<Title text="Hello {/recipient/firstName} {/recipient/lastName}" id="myControl123" />

by its id, like so,

var oTitle = this.getView().byId("myControl123");
oTitle.setText("Hello John Doe");

better make use of data binding

<Title text="Hello {DisplayModel>/recipient/firstName} {DisplayModel>/recipient/lastName}"/>

and work on the data model:

var oDisplayModel = this.getView().getModel("DisplayModel");
oDisplayModel.setProperty("/firstName", "John");
oDisplayModel.setProperty("/lastName", "Doe");

This pays off especially when working with dynamic arrays being visualized by lists or tables! You feed the model with updated data and data binding will re-render the controls for you automatically.