Once you have the network diagram,you can focus on the critical path- this should identify ways to reduce the overall proection duration.
think about-1.Are the task necessary 2.are the task duration reasonable 3.Are all the constraints/dependencies really applicable 4.Can a succesor task be overlapped with the previous one,rather than waiting for its fall complexion? 5.Spilliting the prodecessors task?
The plan should be based on realistic assessments of the available resources,But at this stage you have not looked at specific resource availability-e.g people who have specialised skills maybe needed for specific tasks.
So resource leveling tries to adjust a plan to take a correct resource constraints.
Also take into account when in the year will key activities occur?ie christmas,avoid summer holidays ets also include bank holiday in the planning
Allow for staff taking holidays and also having others work whilst the project,think about how you allocate work to people,should people be given just one assignment to be done at once?Arguably focuses their mind and removes a potential excuses for delay.
Revisiting the plan to see how the project can be completed quickly or brought back to target after earlier delays.The problem here is that costs are likely to increase(e.g overtime pay,hiring etc or quality scope may increse
The starting point should be focus on activiteis on the critical path and saving feels directly into a shorter project duration.For each one look at how much time can be saved by working in a different way 9eg using more people,better machinery)how much time will be saved and what will be the impact of quality scope?Put the options in decending order and ask the project sponsor what they want to do?