What age can you start certain foods?

My DS is nearly 7 months and old and has been trying solids since 4.5 months. He LOVES it!!!! So different from my DD who never ate a thing till 15 months. So it's all a bit new for me. I know there are guidlines but because he started eating a bit earlier (and eats so much) when can I start giving him more? This is what he usually has each day:

MORNING Breastfeed then Rafferty's cereal mixed with apple/pear

LUNCH Breastfeed then lunch of mixed vegetable (whatever we have!) and sometimes rice and small amount of meat. Also some yoghurt or custard

AFTERNOON Breastfeed then either more vegies or fruit and custard

DINNER is usually a small meal of fruit or custard/yoghurt

He has rusks in between.

When can I start him on pasta and cheese? What other foods can I give him knwoing that really he should only be tasting with breastmilk as his main fod - but he LOVES both!