What are the factors to be considered while preparing budget for any construction project?

Effect of  time on  currency rate and inflation 

effect of rework and delayed paymnts on the manpower cost

risks and the  cost to mitigate

1- BOQ Items

2- Quality & Risk

2- WBS

3-Duration and Resources of each activity

4-Activities Relationship

5-Ovarall project duration

4 resources must be consider while ur planning.

1.Money

2.Material

3.Time

4.Manpower

And u can get complete knowledge about these thing by reading BOQ.