Standered req. gathering processes

Plz let me know what are the standered processes used in for gathering req.
means what are teams interacting with client in various phases of SDLD,tools, docs,templates they used
Actually my organization is very small around 10-15 people working and are not finacially strong , in the lach of proper req. gathering ,we have to rework and our time goes into creap.
plz tell me if somebody has idea to share and fit into my samll organization.