How do I estimate my Bitcoin transaction fees?

Could you please elaborate on how one can accurately estimate the transaction fees for Bitcoin? Given the volatile nature of cryptocurrencies, it's crucial to have a clear understanding of the costs involved before initiating a transaction. Are there any specific tools or platforms that provide reliable fee estimates? Are there any factors that should be taken into consideration, such as the current network congestion or the size of the transaction? Understanding these details could help ensure that my transactions are both cost-effective and efficient.