Though each bitcoin transaction is recorded in a public log, names of buyers and sellers are never revealed – only their wallet IDs. While that keeps bitcoin users’ transactions private, it also lets them buy or sell anything without easily tracing it back to them. That’s why it has become the currency of choice for people online buying drugs or other illicit activities.

A BTC wallet is like a real wallet filled with cash. You should never keep all your eggs in one basket and the BTC wallet is no different from this age old idiom. So far there is no air tight solution to keeping your BTC safe and secured...the following action items that can help protect your BTC investment: Backup and encrypt your wallet, make multiple copies of your backup, store them in more than one secure location and finally, don't keep all your BTCs in one wallet.
Markets are dirty. But this doesn‘t change the fact that cryptocurrencies are here to stay – and here to change the world. This is already happening. People all over the world buy Bitcoin to protect themselves against the devaluation of their national currency. Mostly in Asia, a vivid market for Bitcoin remittance has emerged, and the Bitcoin using darknets of cybercrime are flourishing. More and more companies discover the power of Smart Contracts or token on Ethereum, the first real-world application of blockchain technologies emerge.
In a recent report, Goldman Sachs explained that the Chinese yuan is the most popular currency on which bitcoin trades are based. According to the investment bank, 80% of bitcoin volume is exchanged into and out of Chinese yuan. Meanwhile, says that nearly 78% of all bitcoin trading volume is happening on China-based exchanges OKCoin, BTC China, or Huobi. Which suggests that frequent trading between bitcoin and rival fiat currencies would be a common practice. 
The quickest way to make money through Bitcoins is that you should go straight to the markets. Go for the reputable and reliable Bitcoins exchanges operating in the market. Its similar to foreign exchange (forex), where fiat currencies from across the globe are traded 24 hours a day. But it will be more beneficial for you to learn and understand cryptocurrency trading techniques and tactics before involving in any trading procedure. You can find some decent learning resources here.

The best bitcoin exchange is needed for serious and professional bitcoin traders. Bitcoin security must be impeccable. Banking relationships must be sound and reliable. The trading engine must be fast. Order types must be advanced. And profits must be able to be multiplied with Bitcoin margin trading so you can leverage long bitcoin positions or short bitcoin positions.
Interestingly, both resistance and support levels are usually set around round numbers e.g. 10,000, 15,000 etc. The reason for that is that many inexperienced traders tend to execute buy or sell orders at round price points, thus making them  act as strong price barriers. Psychology also contributes a lot to support and resistance levels. For example, until 2017, it seemed expensive to pay $1,000 per Bitcoin, so there was a strong resistance level at $1,000. Once that level was breached, a new psychological resistance level was created: $10,000.
Localbitcoins is quite a popular for p2p (person to person) transactions all over the world. Simply put, you interact directly with the guy selling to you. Out of all the bitcoin sites listed here, this is one of the first and most reputed. Escrow and dispute resolution is provided by the site. See my thorough review of Localbitcoins, I personally use it to cash out of positions quite often.
Bitcoin has evolved in recent years into a speculative investment for individuals seeking alpha from alternative assets and a possible hedge against global uncertainties and weakness in fiat currencies. Bitcoin (BTC) is a digital floating exchange that is pegged to the U.S. dollar like in foreign exchange (forex). However, unlike gold, there is no underlying physical asset on which one can base the price.
A lot of people have made fortunes by mining Bitcoins. Back in the days, you could make substantial profits from mining using just your computer, or even a powerful enough laptop. These days, Bitcoin mining can only become profitable if you’re willing to invest in an industrial-grade mining hardware. This, of course, incurs huge electricity bills on top of the price of all the necessary equipment.

Scalping: This day-trading strategy is becoming popular lately. Scalping attempts to make substantial profits on small price changes, and it’s often referred to as “picking up pennies in front of a steamroller.” Scalping focuses on extremely short-term trading, and it’s based on the idea that making small profits repeatedly limits risks and creates advantages for traders. Scalpers can make dozens—or even hundreds—of trades in one day.
But, once again, be warned. Just because it's a digital currency doesn't mean you won't lose real cash money trading in it. And given that the current Bitcoin market is more volatile than a bag of plutonium nitrate, multi-explosive, sound seeking projectiles, you stand a very good chance to lose a lot of money, especially if this is your first foray into day trading. So unless you have cash to burn or you're already a grizzled day trading veteran, you might want to take one more look at mining after all.
Nigel Dodd argues in The Social Life of Bitcoin that the essence of the bitcoin ideology is to remove money from social, as well as governmental, control.[125] Dodd quotes a YouTube video, with Roger Ver, Jeff Berwick, Charlie Shrem, Andreas Antonopoulos, Gavin Wood, Trace Meyer and other proponents of bitcoin reading The Declaration of Bitcoin's Independence. The declaration includes a message of crypto-anarchism with the words: "Bitcoin is inherently anti-establishment, anti-system, and anti-state. Bitcoin undermines governments and disrupts institutions because bitcoin is fundamentally humanitarian."[125][124]
On 1 August 2017, a hard fork of bitcoin was created, known as Bitcoin Cash.[104] Bitcoin Cash has a larger block size limit and had an identical blockchain at the time of fork. On 24 October 2017 another hard fork, Bitcoin Gold, was created. Bitcoin Gold changes the proof-of-work algorithm used in mining, as the developers felt that mining had become too specialized.[105]
Cryptocurrencies are a potential tool to evade economic sanctions for example against Russia, Iran, or Venezuela. In April 2018, Russian and Iranian economic representatives met to discuss how to bypass the global SWIFT system through decentralized blockchain technology.[56] Russia also secretly supported Venezuela with the creation of the petro (El Petro), a national cryptocurrency initiated by the Maduro government to obtain valuable oil revenues by circumventing US sanctions.
Though transaction fees are optional, miners can choose which transactions to process and prioritize those that pay higher fees.[68] Miners may choose transactions based on the fee paid relative to their storage size, not the absolute amount of money paid as a fee. These fees are generally measured in satoshis per byte (sat/b). The size of transactions is dependent on the number of inputs used to create the transaction, and the number of outputs.[3]:ch. 8