This happens all over India not just in India. Whilst I was visiting the Hussainabad Imambara, a guide showed me around and I gave a donation but then at the end he asked for more guide money which I refused as I said I didn't ask for a guide and that I had already given a donation. He and another guy got a bit shirty but I stood my ground and told them that they had just spoilt the experience and that they shouldn't just keep on demanding tourists for money all the time (even though I was the only tourist there).
It's not a good idea to visit any monuments after sunset and especially if alone.
Ladies should avoid short and sexy clothes on the street., because it's a bit conservative city so avoid attracting unnecessary attraction.
Can be a bit heavy for white women, you stand out and are a relative rarity. Still on the whole a safe place.
take care round the university, there is some fairly heavy folk involved in student life, and kidnappings are not rare.