For one, tilt stick is mandatory on Ryu.
FIRST AND FORMOST: PRACTICE SPACING. THIS IS BY FAR THE MOST DIFFICULT PART OF PLAYING RYU CORRECTLY.
To give you a really quick tip as to how to space effectively with Ryu, again, tilt stick helps. With tilt stick, you can do auto fastfall B-airs by holding down and doing a C stick B-air at the apex of your short hop.
Just in general, get REALLY COMFORTABLE with his movement and range. The sooner you can figure out neutral, the easier everything else will come together.
U-tilt and D-tilt combos into SRK are most easily set up as ledge traps. Spam them on your opponent's ledge getup to cover options and then confirm into SRK as appropriate. Read the occasional ledgeroll, and if you find it difficult to TSRK ledge jump, just remember that spacing your B-air correctly will help you a lot in getting those crucial kills.
Ryu's combos can be devastating, but the real depth to the character is his varied and intricate neutral game. You have some of the best pokes in the game, but your movement tends to be high commitment and requires a lot of finesse to execute safely.