My sister is inviting me to visit her in us. What are the requirements needed for this.

Proofs that you still have plan to come back

1. title of land, business property named after you, car and other properties.
2. money that can support your stay in the US, preferably bank account with activity
3. commitment here: job, contract, schooling etc
4. visa
5. passport

If you're financially capable, there's should be no problem. Check this link too http://travel.state.gov/visa/visa_1750.html

US embassy is very strict to Filipinos and really doesn't care why you're going to US. They are looking into things that make sure you'll come back. So if you're all depending your travel finances to your sister (which is very very common when processing things like this), you won't make it.

This will be very difficult.. you will need strong ties to your home country such as job, ownership of properties, etc.

And, you should be able to prove up the temporary nature of the visit, have a detailed itinerary, schedule and return ticket.