If it's faster times you want, it's faster times you'll get. I'm here to show the most important steps to getting faster times on your favourite track. Personally, I enjoy the Silverstone Racing Circuit and Maple Valley circuit the most. This guide will work for most Forza games (3 and above with the exception of 6). With that out of the way, let's get to the get to the actual guide.
The Track: What kind of track is it? Is the track bendy and twisty with mostly corners or does it have more straight-aways and straight line speed? Examine the track and learn its qualities and characteristics so you can adjust accordingly.
Difficulty: If you're playing on easy or hard, don't expect to get high on the leaderboards. The AI on the professional setting put up pretty good times that are close to ranking 5,000. Play the game and get good enough to beat the AI on the professional setting by at least 5-10 seconds or more. However, difficulty setting isn't all that matters. Assists need to be turned [b]OFF[/b]. No braking, steering, rewind, driving line on 'braking only' or completely off, TCS can remain on for higher tier cars, and most importantly, NO AUTOMATIC SHITFTING. This is important because automatic shifting does not allow your car to rev as much as it should before shitfing. This slows you down in the long run so turn it off and learn to play with a manual transmission (with the clutch). No worries, it gets easy after a while. On the bright side, these settings earn you more credits for your efforts :D.
Transmission: After learning how to drive while using the manual /w clutch setting, you can move on to learning how to properly shift. When shifting up, be sure to activate the clutch when the you reach the maximum revs possible before red lining (AKA reaching maximum revs) and then immediately shift up. Do not hold the clutch down any longer than you need to because there is not power getting to your wheels if you do so. When shifting down, watch your speed and wait for the revs (or speed) to drop below a certain amount and shift down as quickly as possibly. Be sure that you don't shift to early or shift too far. This will throw unnecessary amounts of power onto the wheels launching you forward.
Gear Ratio and Tuning: Depending on the track, your gears need to be adjusted and tuned. Be sure that you have the required transmission upgrades before tuning. If your car is gearing too slowly or too quickly (varies between classes), adjustment is required. For slow gearing, you should slide to final drive ratio bar to the right for more acceleration. If it's an individual gear that is going slowly, adjust it more towards acceleration. If you're plowing through gears way too quickly, adjust the final drive ratio towards 'speed' or slide the bar to the left. The same goes for if the problem lies within an individual gear. Be careful not to over-adjust or you'll lose top speed and straight line speed.
Common problems: #1. If you make a turn and you're heading for another corner that's close by but you hit the limiter and must now shift up (usually you have to brake a little for the corner too) right before the corner, adjust that gear a little more for speed.
#2. You're on a straight-away and on the 5th gear, however, you car is struggling to get to fifth and is pretty much stuck. If this happens, adjust the gear a little more for acceleration.
Alignment: Alignment has a number of factors. It effects tire temperature, grip, turn-in response, and stability are some. Camber is one of the most important contributors to proper alignment alongside toe and caster. Without proper alignment, your vehicle will not handle properly making it very important. Your alignment needs to be tuned just right to achieve faster lap times In order to keep this from becoming a tuning guide, a video link will be provided. The formalities have been skipped and I linked you straight the the important parts:
Off-Throttle Turning: This may sound odd but off-throttle turning is very important especially for high speed bends. Off-throttle turning is exactly what it sounds like: lifting off the gas and turning. This is important because lifting off the gas allows for more turn-in response at high and low speeds. This is most important for high speed turns such as slight bends or speedway racing. Lifting off the throttle and turning in helps you keep you speed and also make the turn. As for the apex turns (especially the sharper ones), off-throttle will help you turn in more before you move onto lightly pushing the throttle to full throttle.
Half-Throttle Turning: This is also exactly what it sounds like: pushing down halfway on the gas. This is most useful during hairpin turns so you don't lose speed as your turning. The sharpness of the hairpin decides how much throttle you use.
Proper Braking: Braking too much, too early, or too late can cause slower lap times. Different corners require different amounts of braking force slight bends require light braking and hairpins require hard braking. High speed corners, like the very first turn on the Silverstone Circuit and the last on Tsukuba, require early braking (be sure to not slow down too much) and then you can proceed to go full throttle. Hairpin turns such as the very first turn on the Tsukuba Circuit require later and harder braking if you're looking for fast times. Remember, braking too much or too little affect your lap times drastically.
Corner Blasting: Believe it or not, despite what the solid red racing line says, there are turns you can plow right through at full speed (off-throttle or not) and get to the apex that they lead to. This usually requires immediate and harsh braking. An example of this is the second and third turn of the Silverstone Circuit (not the full track). This is a little method I like to call 'Corner blasting' which means you plow right through or to the turn. This method isn't always usable. Sometimes it's completely up to handling.
Car Tuning: Car tuning is super important. It allows you to get the absolute best out of you car as well as tune the slidey or understeery cars you buy from the store. Tune your car according to the track. Lots of bends, twists, and turns mean tune for handling and cornering. Straight-aways and high speed corners mean tune for speed, braking, and stability. Similar to before with alignment, I'll provide a link to a tuning guide to assist you with your tuning:
'Stella Stig' also has a very good tuning guide so checking out his guides are also well worth it.
Upgrades: Upgrading your cars according to the track is also important. If the track calls for handling and agility, it's not wise to shove more and more power into your car. Focus on tires and aerodynamics. IF the track calls for speed, well, in the wise words of Jeremy Clarkson - "PPOWWWEEEERRRRRR!!!". Needless to say, but your handling and cornering are still very important. Keep that in mind.
Driving Line: The driving line is an excellent way to learn the tracks and turns. It teachers you what lines to follow and how to get through apexes, hairpins, and chicanes. Personally, I use the 'braking only' line to help me with my poor braking perception. However, the racing line LIES at some points. Despite it being solid red, indicating that you need to slow down, you can really carry on with your racing. Be aware of these lies.
GO!: When that racing line turns solid yellow or is slightly turning red, GO! The racing line is basically telling you to go full throttle after that point, As long as you are through the bend, you're free to go full throttle. Accelerating early is necessary for achieving faster times.
I hope following this guide has given you a bit of insight on how to achieve faster lap times. These tips have helped me through getting some good lap times myself. I'm currently working on the Silverstone Circuit with a time of 1:10:262. This takes practice, time, and effort. It won't take you 4 laps. It will take closer to 50. Thanks for reading. Hope I helped!