Demand Forecasting Model Selection

Help me choose and implement the best demand forecasting approach. Our situation:

Product categories: [Types of products]
Historical data available: [Years of data, granularity]
Seasonality patterns: [Describe any seasonal trends]
Promotion frequency: [How often promotions run]
New product introduction rate: [Frequency of new SKUs]
Market volatility: [Stable, moderate, highly volatile]
Current forecasting method: [If any]
Forecast accuracy target: [MAPE or other metric]
Planning horizon needed: [Weekly, monthly, quarterly]

Please recommend:
1. Most suitable forecasting methodology
2. Data requirements and preparation steps
3. Model parameters and assumptions
4. Accuracy measurement approach
5. Process for forecast review and adjustment
6. Technology/tool recommendations