Front/rear gear compatibility

[Pimperial]

Forgive the silly question but I'm fairly new to this biking lark (my dad used to always buy my bits when upgrading our mountain bikes).
I've been riding my first road bike (a Carrera Valour) for the best part of a year and I wanted to upgrade the crankset and front derailleur (probably Tiagra or similar) but I don't know if any special considerations need to be made in choosing these parts to be compatible with the existing rear end of the drivetrain?

Perhaps this is common sense, perhaps not, but I would appreciate any useful comments. Thanks.

 

[Landslide]

If you're upgrading Shimano bits with better Shimano bits, then you'll be fine.

 

[monnet]

Yep, Shimano for shimano - you should be ok. It's changes at the rear end that can be complicated (9spd to 10spd, long cage vs. short cage etc).