Almost every delay has a control labeled "feedback". This controls the number of repeats and ultimately the depth. Always start with this control fully counter-clockwise and roll it on slowly. Usually a good delay sound is a combination or finese of the feeback control and the output/balance controls. I generally set the overall balance to 70% direct and 30% effect to start off and roll the feedback control on until I get the depth that I'm looking for.

The response above is indicative of a digital rackmount delay and you might not have that. The delay times though should translate well and 150ms is a good place to start. I will sometimes go as high as 300ms if I want a really BIG sound. If you DO have a digital rack delay then I would recommend setting up the delay first and fine tuning with the low and hi cut controls. Proper use of those can help to put a delay sound right where you want it in your mix and keep it from being too in-your-face.