An on-sight lead, where you flash the route at your first attempt, with no falls, or hangs, or information from other climbers, is the ultimate style of ascent. If you have even the slightest chance of getting the route, go for it. You only get one chance - so make sure all the odds are stacked in your favour.

On-sighting is a difficult skill to acquire, and many climbers' strengths and preferred styles are biased towards redpointing or bouldering. There are two parts to on-sighting - viewing the route, and then climbing it. Particularly during competitions the viewing is an integral part of the on-sight; a huge amount of information can be gained regarding clipping positions, rests and possible blind alleys. The same goes for outdoor climbing, though you must be able to adapt very quickly. On very long routes binoculars may be of some use in spotting holds and sequences.

Before you climb

• Locate the crux and hunt for a resting spot below it from which you can psyche up for the next move or sequence.
• Split the route into sections separated by rests. Each section can then be attacked knowing that a breather is coming up shortly.
• Look for obvious rests like bridges, knee-bars, arm-bars, etc.
• Locate all the bolts and remember where the obvious clipping holds are. Count the bolts and take enough quickdraws with you.
• Notice the chalk, lots in one place may indicate a good rest area. But beware of the hold that everyone slaps for - it could be covered in chalk but still be useless!
• Boot rubber is a sure sign of a key foothold, heel hook or toe lock.
• If possible, work out possible sequences, particularly if it's obvious that a certain hand must be on a certain hold.
• Memorise the position of holds around bulges. This can make a huge difference to the chances of your success!

On the route

Having gained as much information as possible, it's time to psyche up. As with redpointing, you must be completely happy with your belayer, rope, harness, surroundings and anything else that might put you off. Move efficiently over easy ground, don't spend time figuring out the best way if you know the first method you spot will work. Clip from the best spot, this should not be at full stretch, but from the best hold even if this means reaching down a little.

When you reach a rest prepare to adapt. If the arm-bar you spotted doesn't fit, don't waste energy trying everything else but make a decision quickly. While you are resting, weigh-up the options. Purposely climb up a move to get a feel for the holds, clip a bolt and then drop back down. Make sure you use the rest well, using your feet to pull you into the rock. Breathe deeply and relax muscles that are not being used. If footholds are going to be a problem on the next move, put on some tick marks with chalk. Check your rack, if you have used all the draws from one side of the harness move some over.
On sighting is the ultimate mental challenge. When the going gets tough make decisions quickly. You have more chance of success if you read it slightly wrong but go straight away than you do if you hang around working it out and going up and down to feel the holds. Be totally committed. Getting pumped and flopping off should not be an option, go for it, that small edge could be a sinker! Unless you are really run out, 'bottling it' should never even enter your mind. This is one of the key skills to on sighting that is generally overlooked.

When you reach the point where you are about to fall, just give it one more chance. Often you can hang around a few seconds more than you thought. Look at your feet; you may be missing crucial holds. If not, go for it, you were gonna fall anyway!
Tips from the expert

With on sighting you only get one chance - so make it count. Wait until you feel fit and strong and the conditions are good. Warm up properly. However, remember it's only a route and don't explode if you fail. In order to find your limit you have to fall off something from time to time. Analyse where you went wrong, learn from your mistakes and you'll soon be a much better climber.