What to do after you beat the hearthome city gym leader in pokemon diamond?

Answer 1

Cynthia will approach you and tell you about team galactic, and she will tell you to head for Canalave City! If you don't have surf, its in Celestic Town. Now that you can surf, head for Jubilife City and use surf to cross the patch of water. You will find yourself on Route 218, and from there you can go directly to Canalave City. You may challenge the Gym Leader, who is a Steel-type user, but I recommend your pokemon to be at least level 40 before challenging him. Good fire attacks will put his pokemon in their place. His pokemon have a ton of HP, so use some good Fire-type moves! Last of all is his Bastiodon. Disadvantages of his pokemon are that they are slow, and you can use that to your advantage. Bastiodon has 4x weakness to Fighting-type moves, so Staraptor's Close Combat is of good use here. Oh, you can also visit Iron Island by telling the sailor at the Canalave City port that you want to set sail. There you can catch Steelix. Best of all, a guy named Riley will help you take out those Team Galactic Noobs once you meet him at the deepest level of the Iron Island Mine. After that, surprise, surprise, he will give you a Riolu egg!!