I know I'm a little late to the dance, but one more thing to consider.
If you are just running coax up to the antenna elements and using good crimp-on lugs with good hardware and a good conductive grease you've done almost everything.
Now, don't forget to tin the shield where you twisted it to go into the crimp lug. Tin it after you've crimped it, and allow the tinning to go under the coax insulation just a tad. Goes for the center conductor as well if it is stranded wire. This fills the braid/strands and prevents water from wicking up the twisted shield/center conductor leads and into the coax. Water will ruin coax. Then seal the coax with a good quality UV resistant exterior caulk/sealant making sure all entry paths into the coax are blocked and sealed well back over the coax insulation.
When using solder out of doors, use a good quality silver solder. Standard tin/lead solder seems to deteriorate in the weather.
"When you want to know how things really work, study them when they're coming apart." -William Gibson
"People Who Don't Want Their Beliefs Laughed at Shouldn't Have Such Funny Beliefs" -AD5MB
"The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?" -KJ3N
IMGP2657.jpg
As an indicator about the idea of using aluminium solder, the lower antenna in the photo, a 2m Hentenna with reflector, is made by soldering bits together. It was impossible to bend two rectangles in one piece so they're in 2 parts and the cross members are soldered in seperately by drilling holes in two larger tubes and sliding these over the main assembly. Likewise joints are reinforced with a larger tube soldered over.
If you ever had to solder copper pipes into lead pipes, unlikely though, it might be familiar but it's not advisable to heat to much because the solder will never run and the tubes will probably melt (I've done it). There should be just enough heat to force the solder in a sort of pasty form into the joints with a cotton, linen or leather rag and carefully wipe it round to look neat.
The 70cm antenna above is copper so no notes needed for that apart from the fact that the horizontal sections are fibreglass rod wrapped with copper tape to save weight.
I've found that with aluminum antenna elements (tubing), not to plug them on the ends. Water will seep in and when it freezes it'll break. In areas where it doesn't freeze the trapped moisture will cause corrosion. Best to leave the ends open so they can drain.
"Don't put it on the plate if you can't eat it!"