Riding skills - Put them on your check list!
1. Braking - Use front brakes with care! Never on lose dirt (Unless in a very steep down hill decent) and never ever when you are cornering! Applying the front brakes 1/2 way around a corner is the quickest way to taste the dirt.
2. Bumps and Dips - Get out of the saddle! Standing on the pedals will give you greater control and less pain.
3. Pedal power - Most people riding in flat shoes will pedal with the heel or arch. Actually you will get much more efficiency by pedaling with the ball of your foot. Try it - You'll like it.
4. Gears (Who needs em!?) - Its true!..Gears are overrated, over used and can cause stress and frustration! Common mistakes are; Incorrect gear selection, Cross chaining (causes chain to jump and grinding noise) and changing gears while pedalling up hill (or under load) causing the chain to drop or even break.
What you should do; Find a mid range gear you are comfortable with - Leave it in that gear -Pedal faster down hill, slower up hill .
Of course if you face a steep climb, get into a low gear nice and early, not 5 meters up the slope! And in a tail wind head for a top gear and make some hay!... But in most cases leave them alone and keep it simple!