They had a complicated relationship - Edward, Clarence and Richard; Clarence and Richard had often been left together with Cecily and Margaret while Edward was with his father. In the 1470s, things came to a head.
George, Duke of Clarence (1449-1478)
George's reputation has been shaped to a degree by Shakespeare, and the famous line 'false, fleeting, perjur'd Clarence'. Well, much as we might point out that Shakespeare was a thoroughly dull sort of chap, but anyway his job was to entertain, not give a history lesson, for once he might well be on the money. Clarence's behaviour as a rebel with Warwick against his own brother had been outrageous; Edward had forgiven, though unlikely he'd forgotten. Clarence could have sat tight and thanks the stars for his luck; he did not such thing. The fight between Clarence and Gloucester for Warwick the Kingmaker's inheritance demonstrated his greed, his defence of Thomas Burdett arrogance and stupidity, in his murder of Ankarette Twynho, brutality.
Richard, Duke of Gloucester (1452 - 1485)
More ink has been spilled about Richard, so I won't go on. At this point, Richard has very much showed his worth to his brother. He refused to be seduced by Warwick and Clarence, stayed steadfastly loyal to Edward. He'd fought by his side at Barnet and Tewkesbury and proved himself. At 5 foot 8, relatively slight build, Richard had developed Scoliosis and therefore his shoulder may have looked higher than his left; but whatever his physical stature, he'd shown himself loyal and effective. in 1471 he was therefore handsomely rewarded by Edward and given the Neville lands in the north, and leadership in the north over Percy.
The Warwick inheritance
Here's a quick and easy family tree which helps illustrate the point about the Warwick inheritance