What to do if I keep getting rejected from credit cards?

Hi yall! I applied for my first credit cards, so I can get a car. I applied for three Chase cards (including the one for students), and I got rejected every time. The first rejection said I didn’t have enough credit history. The second said I applied for too many cards, and I haven’t gotten a reason for the 3rd yet. I’m not sure how I can start building credit if I can’t get a card? I don’t have a ton saved up, but I have more than enough for a credit card. Any tips on what I should do going forward. Also, if I’ve never gotten a loan or anything, will I have credit, and will my credit be lowered by applying for the cards? It’s weird, because my brother was immediately approved for two of the credit cards I applied for when he was in my exact position. Any advice would be much appreciated!