Patch Those Cracks
Painting the exterior of your house can be a painstakingly slow process, but it gives you an opportunity to inspect your home up close. While you're scraping away at the trim for hours, pay attention to the state of wood clapboards, window ledges and shutters. If you find any broken, cracked or rotted sections, fix them now so they won't come back to haunt you later.
If a piece of wood is rotted through, it needs to be removed and replaced. But if there are just a few cracks or holes, patch them using a professional-grade exterior patching compound. No mixing is necessary; just spackle the malleable putty right into the problem area; smooth it in the opposite direction, let it dry, and then sand the surface smooth. Rough sanding the edges of the hole itself will help the compound to adhere [source: Barhnart et al.].
To ensure a perfectly smooth finish, consider sanding down all wood surfaces. We know it's a huge pain, but at least you can rent or borrow a power sander to cover more surface area in less time. Pay particular attention to the places where bare wood meets existing paint. Use a fine 50- or 80-grit paper to really make those transitions seamless [source: Hurst-Wajszczuk].