Twisting the wires together aids in attaching multiple wires to a single point, but will can make it difficult to modify at a later time, i.e., attempting to remove only one wire. If you are sure that your design won't be changing, twist 'em. Also, insert the wire and make a "U" bend through the hole in the lug so that the wire is firmly touching the lug. Use the solder to hold the wire in place.