I was there a few months ago...
A few things you should be doing.
1. get a pair of "snips" GW makes a nice set, it can cut through metal as well as plastic and keeps your fingers away from joints. Basically its a modified pair of wire cutters. Â
http://store.us.games-workshop.com/storefront/store.us?do=List_Models&code=303891&orignav=300810&ParentID=212673&GameNav=3008102. assemble the model as best you can before you glue anything. check to see its the way you want it.
3. undercoat slowly and lightly, cover everything you can.
4. glue sparingly, too much glue makes a mess and holds worse than just a little glue. Adding more glue means the model wont stick at all. Â The solution they make control tips for plastic glue that puts an ultra thin bead of glue where you want it they cost almost nothing. if the glue still isnt sticking, rough up the join by making little lines on it with a hobby knife, just enough to score it where you cant see, it will give the glue a bit of surface to get in.
5. Keep you fingers out of the way by getting something like this
http://www.a2zhobbies.com/Xacto/Precision_Tools/XAC-75140.htmldeveloped for fly fishing the twin aligator clips hold a body or a leg without hurting it, an keep everything snug so your fingers font have to.