Lots of tips actually:
1) READ THE PLANS
2) STICK TO THE PLANS
3) STICK TO THE PLANS
lol
but I mean it XD
4) Get a meassuring tool in inches if you use metric in your country. Straight edges and squaring tools are a great thing to have around.
5) Get the adhesive suggested in the plans. If not, get samples from others and make a few test runs on scrap wood. This is important.
6) Have the right tools and a clean workspace.
7) Your fingers are more expensive than any pro cab built to spec by a pro. Use power tools with great care.
specifics now:

When trying to screw 2 parts that you just aply adhesive to, put some staples in angle (one tooth of the staple in each part), 5 to 10 will do. That will keep the parts in place until the pilot hole and screw go in. Then you can remove the staples (Before the adhesive cures). Later, the screws can go too.
9) After the adhesive cures, if in doubt (specially if you dont have access to the true PL Premium and have to fall back to other adhesive) use a sealant in the joints. I used a hot silicon gun with good results. Specially in zones where access will be difficult afterwards. (corners!!). Do it right when building, Afterwards it will be more difficult.
10) Do a test run of the cab with the proper driver installed (filler installed) right before carpeting of padding the interior, to test for leaks. Afterwards it will be more difficult.
11) I found that the building of the throat is easy to build if you do something like this: clamp the small panels to the table, present the side over them, drill small pilot holes for the screws, apply adhesive and put0the side panel in place. Use small nails through the pilot holes to keep the panel from sliding off position while driving screws. Remove a nail, put a screw. Follow with the next one. Then turn around the piece and clamp the side to the table and repeat. (Second to last pic) Hope it makes sense.
12) If using a metal grill in the baffle take its thickness into account (IITP). Place the grid over the baffle, staple it and use PLENTY of adhesive along the parts where the throat will meet. Sealing that place afterwards will be a PITA.
Plan ahead and install the throat right afterwards!
If you mess up with the thickness of the grill like I did and the throat and mouth panels dont go exactly over the markings you made along the bottom/top of the cab is not that big of a deal, do your best to keep the inner volume and angles as close to the plans as posible though. It will be ok.
Hope this helps. see ya and good build!