You need to listen your damn songs

That is the sad trouth.
When you start thinking about a transition on your head, when two songs fit together perfectly, or you think it's awsome, just try to do it. If you have a lot a transitions like this in your head, then you can use them well in the mixes.
If you are putting a recorded mix tugether, that is different thing.
You can carefully plan the "Mindf*ck" and the "Hight" of the pople, choosing songs together and imagine their transitions, their order.
For a one hour mix I mostly choose songs that fot more than one hour if mixed, then carfully see them in context of each other, and remove the ones that does not fit... regardless how hit or how cool they are: iF a track doesn't fit in the mix concept don't put it in.
Before recording I practice the mix at least once, or stop at certain transitions to perfect them.
1 hour mix takes at least 3-4 hours to make:
Preparation: The correct hardware setup for the mix
Song selection: Just select some songs for the mix. YOu will immediatelly know which one you will use as intro, and so on, but not don't assemble the playlist yet.
Putting the songs in order: Painful thing but worth it. You usually listen the songs well, try to figure out the order, which 2 songs could have a good transition and so on. In this phase I touch the mixer, try to mix them, see what happens.
Practice mix: Practice the whole mix. You can record this, for later use or just to listen back the mix to perfect it (this is a good point to see how long the mix is exactly)
Recording: Just create the mix with everything you know know, most stuff should be in place.
Mastering: Final touches in the mix using Ableton. If I failed a mix so badly, I didn't notice while mixing, this is the point to correct it. Also I consider removing longer monoton parts from a song that makes you bored, mostly because I "shot over" the length of the mix.
I don't know what music you play but here is a good example:
http://www.mixcloud.com/dj_johnny_Bee/bennyb-ehri-competition-mix-2012-02-24/