Optimizing µTorrent for Speed

Optimizing a Bittorrent client like µTorrent for speed is an easy process: Choose a proper port, clear that port through software firewall and router and adjust internal settings based upon upload capacity of the internet connection.  This guide hopes to set forth clearly the basic "truths" for getting the best download speeds in µTorrent.  There are some programs that claim to optimize speed in µTorrent.  Such programs are a scam and generally contain adware or spyware.  I have seen it said, by the developers of all bittorrent programs, that nothing will increase your download speed in a bittorrent client more than the basic steps set forth herein.  
Note:  This guide is based upon µTorrent version 1.8 and the locations of settings has changed from earlier versions.  If you have an earlier version, then I would suggest you update to the latest version as there is a "highly critical" security flaw in earlier versions of µTorrent as reported by Secunia.

Choosing a proper port  Azureus-Wiki:  Port is Blacklisted
A single port within the 49152-65534 range should be chosen to avoid ISP blocks and possible conflicts with other applications.  The option to "Randomize port each start" should be disabled.  These settings are at Options>Preferences (Ctrl+P)>Connection.

Forwarding the Port:  Essentially this is about setting permission in your software firewall and router for your bittorrent client to send and receive communications.

Router (or modem with firewall) - There are two choices here, Universal Plug n Play (UPnP) or manual forwarding. The choice is basically convenience versus security. UPnP is easy, but has security issues. A router blocks unknown incoming connections at the hardware level and provides significant protection for your computer. Enabling UPnP allows any program to create a port mapping through the router without consent of the owner. I would suggest to at least try manual port forwarding through the router as it is not as difficult as it may seem (especially with the guides) and is safer. In any event, read the following section on UPnP as it is an either/or situation and UPnP will have to be disabled if manually forwarding. 

Again, the router documentation is the best place to look for this information. PortForward.com µTorrent Router Index has guides for almost all routers and µTorrent. Choose the make and model of your router and you will be taken to a page with a guide specific to µTorrent and your router.  Many of the µTorrent client screenshots will be out of date as it is constantly updated, but the information should still apply and the screenshots here should help.  Make certain to also check the Static IP Guide.

Adjusting Internal Settings:  This involves taking a speed test, using the calculator to determine the settings that should be used and inputing those settings in your client.  The most important setting is to cap upload at no more than 80% of your overall upload capacity as there needs to be room for communications to the tracker or else download speeds will suffer.  Download could also be capped (at 90%), but this is not necessary as this is rarely an issue.
µTorrent does have a built in Speed Guide (Ctrl+G), which has links to a speed test, port test and has a pulldown menu of common upload speeds that will automatically make these adjustments.  I ran my µTorrent under both configurations and found my speed significantly better using the below.  There is very little extra work involved and the results make it worth it.

Speed Test: Speedtest.net
First the upload capacity of your internet connection must be determined by taking an online speed test. You should stop all internet activity, including torrents, before taking the test and the test should be taken a few times to obtain a reliable average. Speedtest.net has test locations worldwide and will highlight the one closest to you. Note that the result of Speedtest.net is in kilobits (kb) and bittorrent clients show speeds in kilobytes (kB). This is important as 8kb = 1kB. See Azureus-Wiki: Data Units

Calculator:  Azureus Upload Settings Calculator
Once you have an average upload speed for your connection go to the online Azureus Upload Settings Calculator. Although designed for Azureus, this calculator will work for all bittorrent clients. Enter your average upload speed in the appropriate box and the calculator will automatically give the proper figures to adjust various options in your client.

Peer Sources
At (Ctrl+P)>BitTorrent you will note the "Basic BitTorrent Features" section in the middle of the screen.  These are the Peer Sources for µTorrent.  These sources are enabled by default and should be left enabled (as shown below) as they allow you to connect to more seeds/peers and therefore get better speeds.  These sources include DHT (Distributed Hash Table) and PEX (Peer Exchange) which will allow connections to seeds/peers outside of the tracker and can keep your torrent alive even  if the tracker goes down.  The LPD (Local Peer Discovery) is useful if you are on an extended network as it will search the network for individuals active on your torrents.  If it finds someone, you will be able to receive data at a much higher rate as it will be transferred within your network.