Unfortunately, capacitors have very small labels - it should have a three digit code on it (sometimes among other numbers on both sides, to confuse matters).
Here’s the basics:
471 = 47 plus 1 zero = 470pF
102 = 10 plus 2 zeros = 1000 pF = 1 nF
104 = 10 plus 4 zeros = 100,000 pF = 100 nF
334 = 33 plus 4 zeros = 330,000 pF = 330 nF
NB: capacitor colour/size/shape doesn’t indicate capacitance value, although it does relate to the type of capacitor - ie. ceramics are usually terracotta colour, flat discs.
From experience, the small signal diodes 1N4148 have always been a reddy orange colour and slightly transparent, and smaller than a standard resistor. They should be marked with the code. Power diodes are black and fatter, and zener diodes are a mixed bag of colours (yellow, blue, etc.) They all have the cathode marked (the pointy end of the diode symbol).
