Not writing down the date, time or collecting the appropriate Signatures.
Signatures will be needed for permission/witness reasons and so that responsibility is taken for the information written down.
Including information that is or can be proved incorrect.
Falsyfing information - don't write anything that hasn't been observed or witnessed by yourself/first hand.
Uncertainty and confusion - a tough one
lol .. trying not to write things down if they are unclear or don't make sense - allowing enough time to understand the situation being observed and taking down the information in a factual and objective way ... This will hopefully save the documents content from being called in to doubt at a later date.
All of these things are a great reasons why forms & standard documents usually have signature/date etc areas all built in - reflect the 'officialness of the information being collected & if they don't are adapted !!
lol
Documenting any factors that may potentially distort/mislead or make a documents content unreliable/doubtful is very important so that the reader can make their own mind up about things based on all the information provided... and where appropriate be able to act confidently on it.
Lack of evidencing variables/factors or having seen proof that states things to the contrary may well discredit the information & could cause people to think it is not trust worthy and
disregard it completely = time and energy wasted all round
!!
Things that may affect how the children feel and/or act could be noted on the form, especially where an observation picks up on something that perhaps wouldn't normally happen.
Factors/background information may include - Illness, Treatments, feeling unwell, a new baby, birthday, holiday, moving home, disappointment/fear or excitement ..
Don't make assumptions though, always talk to parents, carers and staff about any questions obsevations may throw up !!
hth .. and let us know how you get on