my tips:
yeah none of you bitches have seen a tidy park from me in centuries, lets just say im a whole lot better now, but heres the rules i stick to

1. drink monster, monster help y'all minds wonder like lonely sheep in a desert wasteland. this will actually help you to find real life insprirations because your brain will go into overdrive so with all the thoughts your getting some of them have gotta be about skating right, you see a spot and youll know it like shit if your drunk/high/hyper! only problem is you might forget, thats what iphone notes are for! (also stops you wanting to give up on your parks when your more active) *phew* that was a long one

2. keep blueprints/drawings of your real-life/adapted/stolen (stealing from other creators is good, anyone will agree) spots so that you know exactly what your doing

3. if you fail at merging pieces and get the red border for no reason, use the above downgrade method to make it the way you want (considering DLC of course)

4. STUFF THE TURKEY (sick bastards!) literally cram all of your creative juice into each and every spot and dont leave blanks like ive done in the past, think what could be leaning against your wall, taking up some space&adding in some detail, and what could be in the distance, coz even backgrounds help with park making - e.g. i tend to use scaffolding, unique planters, random scenery (waterfalls n' shit) and suitable props

5. (MOST IMPORTANT) consider your chosen colours and behold your creation

for a full-sized park using my spot inspiration method ^ you need about 5 good realistic spots, and a hella lotta scenery to make-your-break-through, rather than making everything 100% skateable, because reality is much better than fantasy, i've learned that from the best.