Hydrolysis, Oxidation, Reduction

Is there a straightforward, reliable way of being given a reaction (reactants and products, no intermediates) and deducing whether the reactants underwent: a) hydrolysis; b) dehydration; c) oxidation; d) reduction; e) reduction with addition of an alkyl nucleophile; or f) condensation? I'm talking purely about organic molecules here.

I know the basic definitions of each, but nonetheless it is often not obvious to me which change has occurred. Is there any reliable way to look at the structures and find out?

Yes, understand/learn the outcome of each reaction. You can easily tell which has happened as the product will almost always be different for each reaction

Yeah, so my question is, what to look for in the products (compared with the reactants) to figure out which reaction has occurred.

I think I might be able to suggest what to look for in the case of reduction/reduction by alkyl nucleophile:

Simply put, you will gain 1 or more H atoms during reduction to your overall molecule. The general definition also says "loss of O" is reduction, but in organic terms every example I look at seems to involve H atoms being added (often accompanied with dropping from a triple or double bond to a highly electronegative element, e.g. O, S or N, to a double or single bond). Meanwhile, reduction with addition of an alkyl nucleophile is the same, but instead of H atoms being added, I look for signs that the bonds to highly electronegative elements have dropped in number and that a new carbon chain is present substituted on the C which had been (maybe still is) attached to the highly electronegative element(s). Is this correct? If so, then that means d) and e) are dealt with.

And oxidation? You will decrease the number of bonds to a less electronegative element (e.g. lose H, or decrease bonds with/lose metals or Si), or increase the number of bonds to a more electronegative element (e.g. O, S, N, P, F, Cl, Br, I, ).

The problem really is in hydrolysis, condensation and dehydration - how do I spot these?

it would be easier to explain if you gave an example. Give a example molecule....